ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Column liquid chromatography  (34)
  • Yeast
  • Springer  (58)
  • 2020-2024
  • 1990-1994
  • 1985-1989  (58)
  • 1970-1974
  • 1950-1954
  • 1985  (58)
Collection
Publisher
  • Springer  (58)
Years
  • 2020-2024
  • 1990-1994
  • 1985-1989  (58)
  • 1970-1974
  • 1950-1954
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 116 (1985), S. 1233-1236 
    ISSN: 1434-4475
    Keywords: Stereoselective reduction ; (S)-1-Phenylethanol ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The velocity of reduction of 4-substituted acetophenones by baker's yeast is decreased by electron donating substituents. The steric course, however, is little influenced and (S)-1-arylethanols2 are generally formed with over 90% enantiomeric excess.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1985), S. 87-93 
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondria ; oxi2 mutations ; Functional suppressors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A semidominant nuclear suppressor, callednam6, ofoxi2-V276 mitochondrial mutation has been isolated and characterized. The nuclear character ofnam6 was proved by its retention inrho° strains, lack of mitotic segregation in diploids and meiotic 2:2 segregation in tetrads. The specificity ofnam6 was tested on 315mit − mutations of four mitochondrial genes (oxi1, oxi2, oxi3, andcob-box). It suppresses clearly only three mutations in theoxi2 gene, restoring partially or completely cytochrome aa3 formation. The results suggest a functional character of the suppression.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0983
    Keywords: Sporulation ; Yeast ; Transcription ; Meiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have characterized 46 hybrid phage which hybridize preferentially to mRNA from sporulating cells. Cross-hybridization experiments demonstrate that 27 distinct SPR (Sporulation regulated) sequences are represented among these phage. The SPR genes can be grouped into three classes: early, middle, and late. The early class shows an accumulation of transcripts soon after transfer to sporulation medium and continues to accumulate RNA throughout sporulation. Transcripts of the middle class increase in level at about the time of DNA synthesis, rise rapidly in abundance until meiosis II, then accumulate more slowly for at least the next 3 h. Late gene transcripts begin to accumulate at about the time of meiosis I, increase 10- to 20-fold in the next 2 h, then remain constant in late sporulating cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0983
    Keywords: Posttranslational processing ; Ribosomal protein gene ; Transcript mapping ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of the primary structure of the gene for yeast ribosomal protein S31 revealed two unusual features. First, an intron of 312 nucleotides is located within the 5′-untranslated region. Second, the coding sequence for the known amino-terminal peptide of the protein starts 13 codons downstream of the ATG initiation codon, suggesting that S31 is synthesized as a precursor which undergoes post-translational processing to the mature protein. Primer extension analysis showed that transcription of the S31 gene starts at multiple sites. The 5′-flanking region of the gene contains several, previously described, conserved sequence elements that may play a role in the coordinate expression of yeast ribosomal protein genes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-0983
    Keywords: DNA polymerase ; Yeast ; Immunoscreening ; Cloning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Partially overlapping fragments of the gene encoding yeast DNA polymerase I have been cloned by immunological screening of a yeast genomic library constructed in the phage λ expression vector λgt11. The three gene fragments we analyzed in detail encode part of a yeast protein that has been identified as yeast DNA polymerase I, because it shares with this enzyme a number of antigenic determinants. In fact, the yeast protein fragments expressed by the recombinant phages react with both polyclonal and monoclonal antibodies raised against different, highly purified preparations of DNA polymerase I. Moreover, they can be used to affinity purify antibodies specifically reacting with active DNA polymerase I polypeptides and they compete with the yeast enzyme for binding to antibodies that inhibit catalytic activity. The gene is located on chromosome XIV in the yeast genome, and it is transcribed as a 5.2 kb mRNA.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1432-0983
    Keywords: Mitochondria ; Yeast ; Deletions ; RNA stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two cob − deletion mutants are characterized. One of them, M9410, is deleted for 911 by of the noncoding sequences only which separate tRNAGlu and cob exon 1; it thus lacks most of the sequence encoding the 957 by long cob leader (Bonitz et al. 1982) and some 20 by 5′ to it. The end points of this deletion coincide with 31 by long direct repeats in wild type mtDNA. The other mutant, M9391, is deleted for all cob coding sequences and most of the cob leader sequence but it retains the 5′ terminal 261 by of this leader. Northern analysis revealed that M9410 totally lacks cob mRNA or pre-mRNA. The large deletion M9391 in contrast accumulates a 13S RNA which probably results from transcription through the junction, which ligates sequences of the cob leader to sequences of the cob-oli1 intergenic spacer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1432-0983
    Keywords: Yeast ; Carbon catabolite repression ; Oncogene-related genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The “start” cell division control genes CDC36 and CDC28 have been reported to contain a certain sequence homology to tissue oncogenes (ets and some protein kinase encoding oncogenes respectively). Here we report that temperature sensitive mutations in these genes are suppressed in cytoplasmic “petite” mutants and catabolite repression resistant mutants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1985), S. 253-260 
    ISSN: 1432-0983
    Keywords: Yeast ; RNA polymerase I ; Promoter ; Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Deletions in the promoter region of the 37S pre-rRNA operon in yeast were constructed and analysed in vivo using an artificial ribosomal minigene present on an extrachromosomal yeast vector. Sequences required for correct transcription initiation were found to be located between positions −192 and +15 relative to the start; a 5′-deletion down to position −133 reduces the transcription yield of the minigene at least five-fold. To allow detection of transcription of the minigene in isolated nuclei of yeast transformed with a minigene-bearing plasmid we attempted to increase the minigene copy number. The transcription yield in vivo appeared not to be proportional to the copy number but was found to be greatly enhanced when two or three mini-genes are present in tandem. α-Amanitin sensitivity of transcription of these minigenes in isolated nuclei proved that RNA polymerase I is responsible for their transcription.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 279-284 
    ISSN: 1432-0983
    Keywords: Virus-like particles ; Double-stranded RNA ; Yeast ; Yarrowia lipolytica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Four out of the 24 strains of the yeast Yarrowia lipolytica we have checked for the presence of virus-like particles (VLPs) proved to contain encapsidated double-stranded RNA (dsRNA) molecules, 4.9 kb long. A major VLP polypeptide of MW 80,000 was observed in all 4 cases, and a second one of MW 77,000 in three cases. dsRNA from the VLPs harboring only the larger polypeptide showed little homology with the 3 others. We have found no homology between VLP dsRNAs and host DNA or dsRNAs from Saccharomyces cerevisiae, and no relationship between the presence of VLPs and a possible killer phenomenon in Y. lipolytica.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-0983
    Keywords: D-xylose fermentation ; Yeast ; Protoplast fusion ; Ploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protoplast fusion technique was employed in the preparation of presumptive diploid, triploid and tetraploid strains of the D-xylose fermenting yeast C. shehatae CBS2779. Prototrophic selection technique was employed for the recovery of presumed fusant strains. The hybrid nature of the presumptive diploid, triploid and tetraploid strains was confirmed by analysing I) the nuclear condition; II) the cell size and the cell volume of the parental and fusant strain; III) the cellular DNA content and IV) the induced and spontanenous mitotic segregation of properties in these strains. The increased level of ploidy was found to have an effect on the rate of ethanol production from D-xylose.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 533-538 
    ISSN: 1432-0983
    Keywords: cDNA hybridisation ; UV inducible RNA ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Differential colony hybridisation has been used to identify DNA sequences in Saccharomyces cerevisiae corresponding to RNA transcripts whose levels increase 5–10 fold following UV-irradiation. Four sequences have been identified, three of which share sequence homology and hybridise to the same set of genomic DNA fragments. The fourth sequence appears to be distinct, however each DNA sequence hybridises to a similar sized RNA transcript which is approximately 4.0 kb long. The relationships between these DNA sequences and their potential protein products is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1432-0983
    Keywords: Yeast ; TEF genes ; Gene disruption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two genes,TEF1 andTEF2, encode the protein elongation factor EF-1α in the yeastSaccharomyces cerevisiae. We have generated yeast haploid strains containing eitherTEF1 orTEF2 interrupted by insertion of a large piece of foreign DNA. Cells which contain either one functional copy of the EF-1α genes are viable. In contrast, attempts to isolate a yeast haploid strain with bothTEF1 andTEF2 inactivated have failed suggesting that the double gene disruption is a lethal event.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    ISSN: 1432-0983
    Keywords: Yeast ; cdc8-1 mutation ; Mitotic recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a diploid strain homozygous for the cdc8-1 mutation, a block in DNA synthesis caused by restrictive temperature resulted in a significant increase in the frequency of intragenic recombination at the HOM2 locus. Under restrictive conditions, incorporation of radioactivity into DNA was reduced to 2% of the control and alkaline sucrose gradient centrifugation revealed that only short DNA fragments were synthesized. There was no considerable fragmentation of template DNA during incubation of cdc8-1 strains under restrictive conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    ISSN: 1432-0983
    Keywords: Telomeres ; Recombination ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Natural termini from macronuclear DNA of the ciliated protozoans Tetrahymena thermophila and Oxytricha fallax can support telomere formation in yeast. However, plasmids carrying these ciliate termini are modified by the addition of DNA which hybridizes to the synthetic oligonucleotide poly [d(C-A)], a sequence which also hybridizes to terminal restriction fragments from yeast chromosomes but not to Tetrahymena or Oxytricha macronuclear DNAs. Thus, in yeast, the creation of new telomeres on ciliate termini involves the acquisition of yeast-specific terminal sequences presumably by either recombination or non-templated DNA synthesis. The RAD52 gene is required for the majority of yeast mitotic and meiotic recombination events. Moreover, the absence of an active RAD52 gene product results in high rates of chromosome loss. Here we demonstrate that terminal restriction fragments from Tetrahymena macronuclear ribosomal DNA (rDNA) support the formation of modified telomeres in a yeast strain carrying a defect in the RAD52 gene. Moreover, linear plasmids bearing these modified ciliate termini are stably propagated in rad52 − cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 259-262 
    ISSN: 1432-0983
    Keywords: Yeast ; Ty1 ; Trans ; Deletion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DEL1 strains of the yeast Saccharomyces cerevisiae exhibit a high rate of deletions of the three linked genes, CYC1, OSM1, and RAD7. Classical genetic methods showed that DELI segregated as a single Mendelian gene closely linked to CYC1. In addition, genetic evidence suggested that DEL1 was both cis- and trans-dominant (Liebman et al. 1979). Molecular analysis of deletions isolated from a haploid DEL1 strain established that deletion formation was mediated by recombination between yeast transposable elements, Ty's (Liebman et al. 1981). We now report the molecular characterization of deletions isolated from diploids in the trans configuration. This analysis reveals that these deletions probably arose in a two-step process involving mitotic recombination followed by Ty-mediated deletion formation in cis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 285-291 
    ISSN: 1432-0983
    Keywords: Killer toxin ; Plasmid selection ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Transformants of sensitive yeast strains containing an expressed cDNA copy of the yeast killer toxin-immunity gene could be selected for by exposure to added killer toxin. For strain AH-22 the transformation frequency was approximately 10% that obtained by selection for leucine prototrophy. The procedure required time for expression of immunity prior to selection, and a screening step to remove non-transformed survivors. Under conditions where active toxin was produced, transformants containing the toxin-immunity gene were at a selective advantage, and cells losing the plasmid were killed. This resulted in self selection of transformants, and affords a way of maintaining plasmid stability in protrophic strains.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    ISSN: 1432-0983
    Keywords: Yeast ; Ribosomal protein gene ; Sequence analysis ; Conserved elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Computer analysis has previously revealed the presence of a 12-nucleotide common sequence element (AACATC CA TG T A G CA; HOMOL1) in the upstream regions of several yeast ribosomal protein genes. By extending the sequence analysis of the 5′-flanking regions of a number of other ribosomal protein genes (including those encoding S10-1, S10-2, S33 and L16-2) we could establish that HOMOL1 occurs upstream of most but not all yeast ribosomal protein genes. Apart from HOMOL1 an additional conserved sequence (ACCCATACATT A T ; RPG-box) was detected in front of nearly all yeast ribosomal protein genes, although in some cases it is present in the opposite orientation in the other strand. There seems to be no correlation between the occurrence of one box and that of the other. However when both boxes are present the RPG-box is always located 3′ to the HOMOL1-sequence mostly at a distance of only a few nucleotides. A further one-to-one comparison of the upstream regions of several yeast ribosomal protein genes revealed extensive additional sequence homologies that are suggested to be involved in the coordinate control of ribosomal protein gene expression in yeast.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 529-532 
    ISSN: 1432-0983
    Keywords: Yeast ; UV-inducible proteins ; rad mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two UV-inducible proteins have been detected in the yeast, Saccharomyces cerevisiae. The proteins have molecular weights of 78,000 Daltons and 23,000 Daltons. This induction is specific for UV-irradiation as exposure to X-rays, mitomycin C and heat shock does not result in the synthesis of the proteins. The larger (78 kD) protein is induced in various rad strains and in a π° cir° strain. Attempts are being made to isolate the genes coding for these inducible proteins.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 653-660 
    ISSN: 1432-0983
    Keywords: Gene expression ; Yeast ; Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Efficient expression of theEscherichia coli ZeuB (ß-isopropylmalate dehydrogenase) gene occured in yeast after in vitro DNase digestion and religation of plasmid bound ZeuB and the yeastIIIS3 DNA which placed the 5′ end of the yeastHIS3 gene immediately adjacent to the coding region of theE. coli leuB gene. Two structurally distinct classes of gene fusions were constructed, each involved portions of the yeastHIS3 gene which contributed DNA sequences responsible forleuB expression in yeast. The first class involved fusion of theHIS3 coding region to bacterial DNA resulting in the production of a fusion protein with ß-isopropylmalate dehydrogenase activity. The second class consisted of bacterial DNA, including theleuB coding region, fused to theHIS3 promotor region with the absence of any portion of theIIIS3 coding region. In both constructions theIIIS3 promotor region is required for transcription, however, translation of the class two fusion is initiated at a bacterial DNA coded AUG, and the 5′ end of the mRNA coded by theleuB gene mapped predominantly at bacterial DNA sequences. The DNA sequence responsible for the 5′ end of theHIS3 mRNAs remain in the class two gene fusions but this did not preclude the initiation of transcription at bacterial DNA sequences. The pattern of mRNA initiation at bacterial DNA suggests that DNA sequences at, or adjacent to, the site of transcription initiation are involved in the determination of the sites of initiation, and perhaps the frequency at which initiation occurs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 147-155 
    ISSN: 1432-0983
    Keywords: Killer ; Yeast ; Linear plasmid ; Sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Some strains of the yeast Kluyveromyces lactis contain a pair of linear DNA plasmids, k1 and k2, 8.8 and 13.8 kilobase pairs long, respectively. Simultaneous presence of the two plasmids confer a killer phenotype on the cell by producing a toxin which blocks the growth of sensitive yeast species. Previous genetic studies have suggested that the toxin protein is coded by the k1 plasmid. We have now determined the total nucleotide sequence of k1 DNA. The genome is 8,874 base pairs in length. It contains four protein-coding reading frames, three transcribed from one strand and the fourth transcribed from the complementary strand and has terminal inverted repeats of 202 base pairs. Nuclease S1 mapping confirmed this arrangement and showed that these genes are transcribed. The terminal repeats and the four genes form an extremely compact genome, with some overlapping of genes. All four genes use highly biased codons, 86% of them having A or T at the wobble position, reminiscent of yeast mitochondrial genes. Three genes share a very similar 5′ leader sequence. The nature of gene products is discussed in the light of what is known of the excreted toxin protein.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 179-181 
    ISSN: 1432-0983
    Keywords: Blasticidin S ; Yeast ; Resistant mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Blasticidin S-resistant mutants of S. cerevisiae were isolated and characterized. Resistant mutations were found to fall into two complementation groups. A single recessive nuclear gene was responsible for each group, donated as bls1 and bls2, respectively. A gene bls1 was linked to an ilv3 gene located on the right arm of chromosome X. The resistant phenotypes from both genes were not associated with ribosomes known to be target sites of Blasticidin S, when analyzed by poly(U)-directed polyphenylalanine synthesis. The resistant mechanisms of the mutations are discussed in this paper.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 427-433 
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial mutations ; Informational suppressors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ten nuclear suppressors (nam mutations) of the mitochondrial oxi1-V25 ochre mutation are characterized. They restore to some extent the functional form of cytochrome oxidase, as judged by the results of growth tests, cytochrome spectra, cytochrome oxidase activities, and electrophoresis of the products of mitochondrial translation. The nam mutants can suppress some mit − mutations mapping in four mitochondrial genes. They act on a number of chain-terminating mit − mutations. When grown on glycerol medium some double mutants nam x-V25 show an increased sensitivity to paromomycin, while the growth of others is stimulated by the drug. The nam mutants are probably omnipotent suppressors resulting from mutations in nuclear gene(s) specifying mitoribosomal protein(s).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 9 (1985), S. 553-560 
    ISSN: 1432-0983
    Keywords: Yeast ; Ty element ; Recombination ; Gene conversion ; Regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A haploid yeast mutant carrying a reciprocal translocation was analyzed. Cloning and comparison of sequences involved in the translocation event in wildtype and mutant revealed that the crossover between non-homologous chromosomes has occured within Ty sequences. By DNA sequence analysis it could be demonstrated that the reciprocal recombination event is accompanied by a short segment of non-reciprocal exchange (gene conversion) in the immediate vicinity of the crossover. Analysis of the translocation mutant and revertant isolates also indicated that the regulatory effect of Ty elements on adjacent genes can be modified by discrete changes within a Ty element.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    ISSN: 1432-0983
    Keywords: Mitochondria ; Mutation ; Yeast ; Selection ; Random drift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Haploid yeast cells have about 50 copies of the mitochondrial genome, and a mutational event is unlikely to affect more than one of these at a time. This raises the question of how such cells, or their progeny, become fixed (homoplasmic) for the mutant alele. We have tested the roles of six hypothetical mechanisms in producing erythromycin-resistant mutant cells: (i) random partitioning of mitochondrial genomes at cell division; (ii) intracellular selection for mtDNA molecules of one genotype; (iii) intracellular random drift of mitochondrial allele frequencies; (iv) intercellular selection for cells of a particular mitochondrial genotype; (v) induction of mitochondrial gene mutations by the antibiotic used to select mutants; and (vi) reduction in the number of mitochondrial genomes per cell by the antibiotic. Our experiments indicate that intracellular selection plays the major role in producing erythromycin-resistant mutant cells in the presence of the antibiotic. In the absence of the antibiotic, the combined effects of random drift and random partitioning are most important in determining the fate of new mutations, most of which are lost rather than fixed. Our experiments provide no evidence for mutation induction or ploidy reduction by erythromycin.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase ; Codeine phosphate drug substance ; Opium alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid procedure for the evaluation of codeine phosphate drug substance derived from poppy straw or opium concentrate is described. The gradient HPLC procedure employs a pH 2.5 phosphate buffer, methanol and acetonitrile mobile phase at 40°C and a μBondapak C-18 column. Eight opium alkaloids, including the four major alkaloids, are separated from each other. The paper describes details of the assay procedure and presents data documenting the linearity, specificity, precision, and sensitivity of the method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; External variance determinations ; Column and system compatibility ; Microbore and fast LC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The demand for faster, more economic and convenient high-efficiency LC analyses has led to the development of microbore and fast columns. However, to utilize their benefits, the low column dispersions produced by these new technologies necessitate low external variances in the total system. This paper describes the determination of the external variance of microbore, fast and conventional LC systems by a column method. Compatibility with the relevant column technologies is evaluated by a method involving the comparison of the external and column dispersions. Direct comparison of chromatograms of an 8-component mixture, on a set of columns of various diameters and lengths, shows the relative speed, economy and sensitivity obtainable in practice. The problem of reduced sample loadability is considered and the practical solution of peak compression illustrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Retention prediction system ; UV multichannel detector ; Polycyclic aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention prediction system assisted by a micro-computer coupled with an UV multichannel detector has been investigated in the separation of polycyclic aromatic hydrocarbons. The method offered very precise identification of components in NBS-SRM-1647 sample without any standard reference substances. It has been proven that the system makes very precise, non-pollutive and convenient environmental analysis possible.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 313-322 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Tetracyclines antibiotics ; Quantitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of high-performance liquid chromatography (HPLC) for the identification and determination of tetracycline antibiotics is reviewed. HPLC chromatograms provide fast identification by retention time, tR, and precise quantitation by measurement of peak height or peak area. For separation of tetracycline compounds, most HPLC methods use reversed-phase C18 or C8 columns and UV detection. The HPLC solvent system should have a pH of about 6 to prevent steric changes in the tetracycline molecule. For accurate quantitation it is necessary to avoid tailing and this is accomplished by adding a zwitter ion to the solvent system. Methanol and acetonitrile are frequently used as organic modifiers in these solvent systems. In a single analysis, HPLC methods can be used to separate as many as nine or ten commercially used tetracycline compounds and to determine four to five tetracyclines in commercial tetracycline preparations or in biological fluids.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Resolution of optical isomers ; Chiral column ; Pyrethroids ; Fenvalerate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The separation of the optical isomers of fenvalerate [cyano(3-phenoxyphenyl)methyl 2-(4-chlorophenyl)-3-methylbutyrate] has been carried out by high-performance liquid chromatography (HPLC) on a chiral column with (R)-N-3,5-dinitrobenzoyl-phenyl-glycine (DNBPG) covalently bonded on aminopropyl silica and eluted with mixtures of methanol, 2-propanol, and hexane. The system was applied to the analysis of Pydrin®, an emulsifiable concentrate formulation of fenvalerate, and to the residue analysis of fenvalerate in milk samples. For the analysis of Pydrin® the only requirement was the proper dilution of Pydrin® with hexane. For the analysis of residues in milk, fenvalerate was extracted with hexane after precipitating the milk proteins with acetonitrile and removing the precipitate by filtration; the hexane extract was concentrated to small volume and filtered before being analyzed by HPLC.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 487-494 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size-exclusion chromatography ; Controlled-porosity glasses ; Boron-enriched glass surface ; Adsorptive properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Controlled-porosity glasses (CPG) are sieves for macromoleculars, very widely applied in chromatographic columns for the separation of polymers and biopolymers by means of size-exclusion chromatography (SEC) and affinity chromatography. This paper deals with the influence of the thermal treatment of CPG on the elution of polymers in SEC columns. The problem is examined for a few mobile phases and for glasses having different porosities. Additionally, the SEC results obtained are compared with the adsorption properties of the glases investigated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 587-590 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion-pair chromatography ; Sulfonate pairing ion ; Adsorption isotherms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of positively and negatively charged and neutral solutes was studied in an aqueous phosphate buffer eluent, with constant inorganic-counterion concentration, on ODS-Hypersil stationary phase in the presence of various sulfonic acid ion-pairing reagents. The adsorption isotherms of the ion-pairing reagents d-camphor-10-sulfonic acid, sodium cyclohexylsulfamic acid and sodium alkylsulfonates (butyl-, hexyl- and octyl-) were determined by the breakthrough method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 615-617 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Vitamin B2 in food ; Column switching ; Liquid-solid extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Vitamin B2 was enriched by liquid-solid extraction from large volumes of aqueous samples on a short precolumn. The enriched compounds were transferred onto an analytical reversed-phase column and separated by ion-pair chromatography. The equipment used provides the possibility of automation for routine analysis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Controlled-porosity glasses ; Chemically bonded phases ; Boron-glass surface enriched
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In the preparation of C18-bonded phases higher coverage densities were obtained using dimethylaminodimethyl-n-octadecylsilane than chlorodimethyl-n-octadecylsilane as the reagents. The HPLC results show the very high hydrophobicity of the materials obtained. The elution mechanism has been found to be independent of the coverage density on the boron-enriched glass surface in the range 2.3–4.0 μmol/m2.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Direct injection of biological samples ; New quinitidine metabolites ; Deproteinisation on precolumn ; Column switching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary New quinidine metabolites, including 10,11-dihydrodiol quinidine N-oxide, 10,11-dihydrodiol quinidine and their glucuronides, were found in human urine. A quinidine monitoring HPLC method including these metabolites, is proposed by the direct injection of body fluid samples onto the precolumn for deproteinization followed by reverse phase separation in the analytical column with a column switching technique. The recovery of spiked quinidine and its metabolites in plasma was quantitative (98–102%) with good reproducibility (C.V.: 1.6–4.0%). Several clinical samples such as whole blood and urine were analyzed by the present method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Quantitative structure-retention relationships (QSRR) ; CNDO/2-MO Calculations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention data for 12 aromatic test solutes with functional groups of various polarities were studied on a wellcharacterized monomeric octadecyl stationary phase over a range of methanol/water compositions. CNDO calculations on the solute structures and regression analysis indicated that two terms, the total energy, ET, and the maximal difference of electron excess charge, Cd, correlated well with changes in retention as a function of methanol composition. This approach allowed for the non-empirical calculation of retention data for solutes with a range of polarities, overcoming previous deficiencies in the estimation of molecular polarity for non-homologous solutes based on total dipole moment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Weak cation-exchanger ; Styrene-divinylbenzene copolymer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A weak cation-exchanger for high-performance liquid chromatography is obtained by oxidation of either poly(methylstyrene-divinylbenzene) or of poly(chloromethylstyrene-divinylbenzene). Reaction conditions were optimised to yield an exchange capacity of about 4meqg−1 dry resin. The material was evaluated chromatographically as a function of pH, organic modifier, temperature and flow rate. A combination of ionexchange and hydrophobic interaction between the solutes and the packing material was observed. This could be used to provide more options for realising chromatographic separations. Some chromatograms of heterocyclic bases, nucleosides, nucleotides and amino acids are shown.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 87-96 
    ISSN: 1612-1112
    Keywords: Time Optimization ; Column liquid chromatography ; Microbore ; Theophylline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Algorithms for the time optimization of an HPLC separation are presented. Resolution, column performance, extra-column variance, capacity factor, and column length are incorporated into these algorithms. Extracolumn variance for a high-speed microbore system (1 mm i. d. column) was assessed using 2nd moment variance and a non-linear extrapolation of tubing length to zero. Extra-column variance, as a function of flowrate, was incorporated into the reduced operating curve of column performance. The use of empirical correction factors for column reproducibility and homogeneity are suggested. Cutting to an optimum length did not degrade column performance. These algorithms were applied to the optimization of a microbore assay for theophylline, in a simple xanthine mixture. Resulting total analysis times were reduced to 10seconds per sample, at a flowrate of 700μl/min.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Metal complexes ; Tetrakis(4-methylphenyl)porphine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The feasibility of reversed-phase high-performance liquid chromatography for the separation of several metal complexes ofmeso-tetrakis(p-tolyl)porphine (TTP) is described. A combination of an octadecyl-bonded stationary phase with a non-aqueous polar mobile phase, such as an acetone-acetonitrile mixture, has proved effective for the separation. Thus, the TTP complexes of Mg, VO, Ni, Cu, Zn, and Pd and also TTP free acid were successfully separated in about 10min on a Li-Chrosorb RP-18 column (7μm, 250×4mm i.d.) with a 70∶30 (vol/vol) mixture of acetone and acetonitrile at a flow-rate of 1 mlmin−1.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 213-218 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Nitro-PAHs ; Diesel particulate extract ; Column switching-HPLC ; Pyrene-butyric acid stationary phase ; π-acceptor ligands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the determination of nitrated polynuclear aromatic hydrocarbons (nitro-PAHs), in particular 1-nitropyrene, in diesel particulate extracts. The method employs a multidimensional HPLC (column switching) technique with final on-line peak identification by UV-VIS spectral comparison with standards. To achieve exceptional chromatographic selectivity for nitro-PAHs, a new pyrene butyric acid amide phase has been prepared which is capable of forming donor-acceptor complexes with them. With this technique it is possible to confirm the presence of 1-nitropyrene in the range 3–100 ng/mg on filter-collected diesel soot. Its utility was demonstrated with diesel exhaust extracts spiked with varying levels of 1-nitropyrene and proved to be highly selective.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microcapillary column ; Gasoline group analysis ; Conventional IR detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Slurry-packed microcapillary column liquid chromatography with conventional infrared detection is described for the group-type analysis of gasolines. The results indicate that the three eluted groups, saturates, olefins and aromatics, from the microcapillary column are easily detected by conventional microcomputerized infrared spectrometer coupled with a Teflon flow-cell with a good signal-to-noise ratio. This study shows the feasibility of microcapillary column liquid chromatography combined with a low-cost, conventional infrared spectrometer as a routine tool which allows the analyst to use an LC-IR system effectively and economically.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 425-433 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed phase ; Adsorption isotherm ; Dead volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In RPLC the dead volume can be defined as the difference between the maximum column hold-up volume and the volume of the adsorbed phase. The composition of the adsorbed phase depends on the composition of the mobile phase and therefore, the dead volume also varies with it. In this work, the alkyl bonded phase acetonitrile (ACN)-water mobile phase system is investigated. In the system, deuterated water (D2O) and deuterated acetonitrile (D-ACN) are retained due to the isotopic dilution effect. By means of D2O and D-ACN, the absolute adsorption isotherm of the organic modifier ACN is measured. Based on the isotherm, the chromatographic behaviour of ACN, D-ACN and D2O, the variation of the dead volume with the composition of the mobile phase, and the approach to determine the maximum column hold-up volumn are explained. In addition, the various approaches to determine the dead volume are compared and the recommendations are given for the case of common unbuffered binary systems (MeOH/H2O, THF/H2O and ACN/H2O).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Amiloride hydrochloride ; Hydrochlorothiazide ; Quantitative determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A procedure for the simultaneous quantitative determination of amiloride hydrochloride and hydrochlorothiazide by high-performance liquid chromatography is proposed. A reversed-phase LiChrosorb C8 stationary phase is used. The eluent consisted of an acetonitrile/0.1M phosphate buffer pH3 (15∶85) mixture, containing 50mM propylamine hydrochloride. In this system amiloride hydrochloride, a basic drug, eluted with a acceptable asymmetry factor (Asf=2.1). A simple extraction procedure with methanol is used. Relative standard deviations of 0.87% and 1.6% were obtained for amiloride hydrochloride and hydrochlorothiazide respectively. Chlorothiazide, a thiazide diuretic, is a suitable internal standard. Furthermore the method is also specific for other thiazide diuretics, potassium-sparing diuretics and loop diuretics and for the respective hydrolysis productes of both drugs. Analysis time is reduced to a minimum; the chromatographic separation is complete within 6 minutes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 495-499 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; L-tryptophan-serum albumin binding ; Bovine serum albumin ; Human serum albumin ; Binding parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two high-performance liquid chromatography (HPLC) techniques were developed for the determination of binding constants in the interaction of serum albumin with L-tryptophan: internal calibration and external calibration. The results obtained were compared with those obtained by the classical method of equilibrium dialysis and by gel filtration. While all the methods are equally reliable, the internal and external calibration techniques seem to be superior in their simplicity, speed and convenience.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 529-532 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Modified silica gels ; Pyrimidines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The effect of the surface chemistry of bonded-phase column material containing alkyl, phenyl, cyano and amino groups on the adsorption of pyrimidine molecules has been studied by HPLC. The dependence of the retention on the chemical structure of the adsorbed molecules was determined. The influence of the substituents at the pyrimidine ring and their position on the retention character is shown for various bonded phases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 559-565 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reaction detector ; Formaldehyde determination ; Trace analysis ; Cosmetic products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The determination of free formaldehyde in the presence of its donators in cosmetic samples by a combination of reversed phase chromatography and post column reaction detection is described. The free formaldehyde is separated on a RP column with water as eluent from interfering formaldehyde-containing compounds and consecutively determined by the lutidine method in a reaction detector with knitted open tubes. With detection in the visible (420nm) the minimum detectable quantity is 40 ppb, with fluorimetric detection 15 ppb. The sample clean-up procedure for cosmetic products ranging from mascara to shampoo is by extracting the formaldehyde with water of pH 3, where the decomposition rate of the donators is minimal. Smaller amounts of free formaldehyde are always found compared to the standard lutidine method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; FTIR detection ; Aqueous eluents ; Deuterated compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Deuterated compounds have been used as mobile phases for microcolumn high-performance liquid chromatography (HPLC) employing flow-cell Fourier transform infrared spectroscopy for detection. Separations were carried out on adsorption, reversed-phase, non-aqueous size-exclusion and aqueous size-exclusion chromatographic columns. Due to the IR transparency of deuterated compounds in a C−H stretching region they represent nearly ideal eluents in terms of universal detection. In addition, due to the shift in the absorption wavenumber following deuteration, deuterated solvents allow FTIR detection of solutes in other regions, where otherwise it would be prohibited, or sensitivity sacrified by interfering solvent absorption.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Retention volumes ; ODS silica ; Aromatic compounds ; Substituent interaction effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention volumes of monosubstituted benzenes, benzoic acids, phenols and anilines have been measured in reversed-phase liquid chromatography. Buffered acetonitrile-water and tetrahydrofuran-water eluents were used with an octadecylsilylsilica adsorbent. From the net retention volumes a substituent interaction effect was calculated and described with the linear free energy relationship developed by Taft. The positive sign of the values of the ρ-parameters, figuring in this relationship, was interpreted in terms of hydrogen bonding between the solutes and the eluent.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    ISSN: 1612-1112
    Keywords: Donor-acceptor complexes ; Column liquid chromatography ; Caffeine bonded phase ; 7(n-propyl)theophylline silica ; Petroleum residues and asphalts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of a new caffeine phase for HPLC is described. The capacity ratios (k′) of about ten polyaromatic hydrocarbons have been determined. It has been shown that the aromatics were eluted according the number of rings, only slightly influenced by the substituents. The performance of the stationary phase is demonstrated with separations of petroleum asphalts and residues and aromatic mixtures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 179-184 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion chromatography ; Potentiometric detection ; Copper electrode
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A metallic copper electrode housed in a suitable flowcell is shown to be a sensitive and versatile potentiometric detector for ion chromatography. This electrode may be used for direct or indirect detection of many inorganic anions and cations and also for organic acids. In the direct detection mode, electrode response is based on either complexation of copper ions at the electrode surface by eluted species, or on oxidation and reduction reactions for eluted species which are strong oxidants or reductants. Direct detection is therefore applicable to such species as amino acids, organic acids, chloride, bromide, iodide, chlorate, bromate and iodate. Indirect detection is possible for anions which do not complex copper ions, provided a copper complexing ligand (such as phthalate) is used in the eluent; cations which complex this ligand are also detectable. Indirect detection may be used for species such as nitrite, nitrate, acetate, formate, succinate, benzoate, alkaline earth ions and transition metal ions. Electrode calibration relationships are discussed and sample separations are presented, together with some typical detection limits attainable in the direct and indirect detection modes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 239-241 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Bonded phases ; Anthracene silica gel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary N(9-methylanthracene)aminopropyl silica gel is introduced as a new reversed-phase packing material. It has specific selectivity for some aromatic compounds. In this paper the anthracene phase is compared with commercial octadecyl-, phenyl- and aminopropyl-bonded silica gels.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Amino silica gel ; Neuraminic acids ; UV detection at nanomole level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Neuraminic acid derivatives were separated easily by liquid chromatography on amino phases and using acetonitrile/15 mM phosphate buffer, pH 5.2 as mobile phase. Detection at 200 nm allowed determination of substances in the nanomole range. All solvent systems were used isocratically at room temperature. The separation did not depend on ion-exchange but on a partition mechanism, the solutes being separated according to their polarity. Thus, it was possible to optimize the resolution by varying the stationary phase and the composition of the eluent.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Phenyl bonded phases ; Effect of pore size on retention ; Polycyclic aromatic hydrocarbons ; Silica supports
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Differences in bonded phase properties were studied for triphenyl, diphenyl, phenyl and benzyl phases prepared on a variety of silicas. A total of six silicas with pore diameters ranging from 100 to 200 Å were used in the synthesis. The effect of the pore diameter of the silicas on the retention of polycyclic aromatic hydrocarbons are discussed. Differences in retention were observed as a function of pore size, but not much difference was observed with substrates having pore sizes larger than about 170Å. The observed phenomena are explained by two steric exclusion mechanisms, one during the bonding reaction, and the other in the chromatographic analysis. Statistical calculations were performed using the descriptors showing molecular size and/or shape. The results indicated that the difference between bulky phases and less bulky phases was only observed in the degree of shape-recognition ability of the solute while no differences exist in the retention mechanisms on the different phases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 303-307 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size-exclusion ; Dynamic equilibrium ; Ion-pairing interaction ; Monomer-dimer separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Molecular interaction between uni-uni valent ions and bovine serum albumin was investigated by size-exclusion chromatography. Elution profiles are first presented for salt and protein solutions as samples with water as the mobile phase; then for water and protein as samples with salt solutions as the mobile phase. The results suggest the existence of a dynamic equilibrium between the salt ions and the protein ions as reactants and the ion-pair (salt-protein) complex as a product.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 471-476 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Organic polyselenides ; Molecular area effects ; Comparison with polysulphides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Organic polyselenides in which the selenium chains are terminated at both ends by ethyl-thio, butyl-thio, phenylthio, or phenyl groups were prepared. Their chromatographic behavior in HPLC on a bonded octadecyl phase with entirely or mainly methanolic eluents was investigated and compared with the corresponding polysulphides. The retention increment per Se atom is greater than that for S atoms. The ratio of Se to S increments is equal to the ratio of surface area increments. The S−Se bond does not have an appreciable influence on retention. Bonded to phenyl, selenium increases retention to the same extent as sulphur does. Some of the RSSenSR solutes were identified by mass spectrometry and other techniques.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 13-19 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Open tubes ; Diffusion coefficient ; Calibration curve for oligostyrenes ; Diffusion-averaged molecular weight ; Polydispersity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The concept of a diffusion-averaged molecular weight, Md′ is presented, and Md is defined for polydisperse samples. It is shown via oligostyrene mixtures that Md can be determined in 20 minutes with common chromatographic equipment. If Md is measured and Mn or Mw is known, the polydispersity can be obtained.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Silica gel solubility ; Copper (II) silica gel solubility ; Copper (II) silica gel stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary After summarizing published results on silica gel and alkyl-bonded silica gel solubilities, the experimental solubility of unmodified silica and copper silicate gel (used in ligand exchange chromatography) in watermethanol-ammonia and water-acetonitrile-ammonia mixtures are given. These results demonstrate that silica gel solubility, measured by a static method, varies greatly with the water volume fraction of a ternary mixture. Curiously, no influence from the organic nature of the solvent was demonstrated. This observation is inconsistent with the fact that the copper silicate gel used in ligand-exchange chromatography with water-methanol-ammonia as mobile phase is attacked more rapidly than with water-acetonitrile-ammonia. An explanation based upon the variations of acid-base properties of silicic acid versus mobile phase dielectric constant values in conjunction with the methanol protophilic properties is proposed. Finally, it is shown that chromatographic columns filled with copper silicate gel have lifetimes of several months, if they are used with a procolumn (of copper silicate gel) and with acetonitrile as organic solvent with a volume fraction greater than 0.5 in the mobile phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    ISSN: 1612-1112
    Keywords: Hydrolysis, high temperature ; Column liquid chromatography ; Ion-exchange ; Cellulose ; Oligomeric and monomeric sugars
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The hydrolysis of different cotton materials under hydrothermal conditions was investigated. For the analysis of the resulting reaction products high-performance liquid chromatography and gel-permeation chromatography were applied. HPLC columns with ion exchange materials as stationary phases (HPX 87P and Shodex S801) enabled the separation of monomeric sugars and degradation products. Oligomeric sugars were analyzed using a gel column (Bio-Gel P-2) as well as a HPLC column (HPX 42A). Through identification of additional reaction products the mass balance of the hydrolysis can be improved and the analysis of the distribution of the oligomeric sugars gives information for the selection of the reaction conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 20 (1985), S. 96-98 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Phthalic anhydride ; Naphthoquinones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple method of analysis of the 1,2 and 1,4 isomers of naphthoquinone in crude phthalic anhydride has been developed. The sample was first dissolved in water at 60°C to quantitatively hydrolyse the anhydride to phthalic acid. Analysis of the aqueous solution by reversed-phase HPLC using 75∶25 methanol:water mobile phase resulted in excellent resolution between the phthalic acid and the naphthoquinones and enabled quantitative measurement of each of the naphthoquinones to 0.1 % in crude phthalic anhydride.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...