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  • 1
    Electronic Resource
    Electronic Resource
    Performance characteristics and regeneration of a tetraphenylboron(III) selective electrode (1987)
    s.l. : American Chemical Society
    Analytical chemistry 59 (1987), S. 1078-1081 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00135a002
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  • 2
    Electronic Resource
    Electronic Resource
    Amineptine Plastic Membrane Electrode Based on its Ion Associate with Tetraphenylborate and Phosphomolybdic Acid (1999)
    Springer
    Microchimica acta 132 (1999), S. 83-88 
    Details
    ISSN: 1436-5073
    Keywords: Key words: ion-selective electrodes; amineptine HCl; sodium tetraphenylborate; phosphomolybdic acid; plastic membrane electrode.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  New amineptine hydrochloride (Am-Cl) ion-selective electrodes (conventional type) based on amineptinium-tetraphenylborate (I) and amineptinium-phosphomolybdate (II) were prepared. The electrodes exhibited mean slopes of calibration graphs of 57.9 mV and 53.8 mV per decade of (Am-Cl) concentration at 25 °C for electrodes (I) and (II), respectively. The electrodes can be used within the concentration range 3.16×10−5−10−2 M (Am-Cl) at a pH range of 2.0–3.9 for both electrodes. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficients of the electrodes, which were 0.00172 V °C−1 and 0.00091 V °C−1 for (I) and (II) electrodes, respectively. The electrodes showed a very good selectivity for (Am-Cl) with respect to a number of inorganic cations and sugars. The standard addition method is successfully applied to determine (Am-Cl) in pure solutions and in amineptine-containing tablets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00010077
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  • 3
    Electronic Resource
    Electronic Resource
    Spectrophotometric Microdetermination of Some Pharmaceutically Impor tant Aminoquinoline Antimalarials, as Ion-Pair Complexes (2000)
    Springer
    Microchimica acta 134 (2000), S. 133-138 
    Details
    ISSN: 1436-5073
    Keywords: Key words: Calmagite; determination of antimalarial compounds; dosage forms.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract.  A simple, rapid, accurate and sensitive spectrophotometric method for the microdetermination of some pharmaceutically important aminoquinoline antimalarials, namely amodiaquine dihydrochloride (I), chloroquine phosphate (II) and primaquine phosphate (III) is described. The method is based on the interaction of these drugs with calmagite indicator to give highly coloured ion-pair complexes which exhibit maximum absorption at 663, 665 and 666 nm, respectively, Beer’s law is obeyed in the concentration ranges 1.0–25.0, 1.0–28.0 and 1.0–33.0 μg/ml for the drugs I, II and III, respectively. For more accurate analysis, the Ringbom optimum concentration ranges are 2.5–22.5, 2.0–26.0 and 3.0–30.0 μg/ml, respectively. The apparent molar absorptivities were calculated. Statistical treatment of the experimental results indicates that the method is sufficiently accurate and precise. The accuracy of the method is indicated by the recovery (99.8±1.4%) and the precision by the relative standard deviation (〉1.5%). The proposed method has been applied to the determination of these drugs in certain formulations, with results that compared favourably with those obtained by the official methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s006040070028
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  • 4
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of ciprofloxacin in pure form and in tablets through charge-transfer complexation reactions (1998)
    Springer
    Microchimica acta 130 (1998), S. 35-40 
    Details
    ISSN: 1436-5073
    Keywords: ciprofloxacin ; 2,3-dichloro-5,6-dicyano-p-benzoquinone ; 7,7,8,8-tetracyanoquinodimethane ; p-chloranil ; spectrophotometry ; charge-transfer complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Three simple, quick and sensitive spectrophotometric methods are described for the determination of ciprofloxacin. The methods are based on the reaction of this drug as ann-electron donor with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), 7,7,8,8,-tetracyanoquinodimethane (TCNQ) andp-chloranil (CL) as π-acceptors to give highly coloured complex species. The coloured products are quantitated spectrophotometrically at 460, 843 and 550 nm for DDQ, TCNQ and CL, respectively. Optimization of the different experimental conditions is described. Beer's law is obeyed in the concentration ranges 5–50, 1.5–15 and 20–200 μg ml−1 ciprofloxacin, but the concentration ranges for best accuracy are 10–48, 2.5–15 and 35– 195 μg ml−1 of drug for DDQ, TCNQ and CL, respectively. The relative standard deviations are less than 1.5%. Applications of the suggested methods to ciprofloxacin tablets are presented and compared with the USP method. The stability constants of the 1∶1 DDQ and CL complexes were 1.086 × 104 and 2.581 × 104 lmol−1, respectively, whereas for the 1∶2 TCNQ complex it was 3.62 × 1081. mol−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254588
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  • 5
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of 6-aminopenicillanic acid using bromophenol blue and bromothymol blue (1995)
    Springer
    Microchimica acta 117 (1995), S. 187-194 
    Details
    ISSN: 1436-5073
    Keywords: 6-aminopenicillanic acid ; bromophenol blue ; bromothymol blue ; spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two simple, selective and sensitive spectrophotometric methods are described for the determination of 6-aminopenicillanic acid (6-APA). The methods are based on the reaction of 6-APA with either bromophenol blue (BPB) or bromothymol blue (BTB), to give orange-red and green species, respectively. The coloured products are quantified spectrophotometrically at 625 and 616 nm for BPB and BTB, respectively. The optimization of the different experimental conditions is described. No interferences from different β-lactams and common degradation products were observed in the determination of 6-APA using BTB, while flucloxacillin, dicloxacillin, adrenaline, vitamin C, urea and common degradation products in any percentage interfere on using BPB only. The BTB method was better than the BPB method, because of its wider range of determination (0.4–20 μg ml−1 vs. 0.4–7.2 μg ml−1 on using BPB), higher molar absorptivity and Sandell sensitivity (3.27 × 103l mol−1 cm−1 and 0.099 μg cm−2 vs. 2.82 × 103lmol−1 cm−1 and 0.115 μg cm−2), greater stability (3 and 10 days on using BTB and BPB, respectively) and better selectivity. The results were compared with those given by the Official United States Pharmacopeial XXI method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244889
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  • 6
    Electronic Resource
    Electronic Resource
    Conductometric titration of pindolol and propranolol using ammonium reineckate and potassium tetracyanonickelate (1995)
    Springer
    Microchimica acta 118 (1995), S. 85-91 
    Details
    ISSN: 1436-5073
    Keywords: pindolol ; propranolol ; reineckate ; tetracyanonickelate ; conductometric titration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A simple and sensitive conductometric method for the determination of 2–24 mg of pindolol and propranolol hydrochlorides using ammonium reineckate and potassium tetracyanonickelate in an ethanol-water mixture is described. The effect of the solvent ratio, reagent concentration, time and temperature on the shape of the titration curve is studied. Statistical treatment of the experimental results indicates that the method is precise and accurate. The accuracy of the method is indicated by the excellent recovery (98.2–101.2%) and the precision is supported by the low standard deviation value 〈 0.10. The sensitivity of the proposed method is discussed and the results are compared with the pharmacopoeial non-aqueous titration method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242231
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  • 7
    Electronic Resource
    Electronic Resource
    Potentiometric sensor for phenylephrine based on phenylephrine-tetraphenylborate lipophilic salt (1989)
    Springer
    Microchimica acta 99 (1989), S. 101-108 
    Details
    ISSN: 1436-5073
    Keywords: phenylephrine ion-selective electrode ; poly(vinyl chloride) membrane ; drug analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Phenylephrine (PE) ion-selective electrode based on incorporation of phenylephrine-tetraphenylborate lipophilic salt in plasticized PVC matrices is constructed. The electrode shows near Nernstian response over the concentration range 1.5 × 10−4-10−1 M in solutions of pH 2.9–8.0 at 25°C. The electrode resists the effect of heat in the temperature range 25–55°C exhibiting an isothermal temperature coefficient of 0.0007 V/°C. The selectivity of the electrode for PE towards large number of inorganic cations, sugars and amino acids is investigated. Determination of PE in an eye-drops pharmaceutical preparation is carried out using the proposed electrode as potentiometric sensor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242795
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  • 8
    Electronic Resource
    Electronic Resource
    Construction and Analytical Applications of Plastic Membrane Electrodes for Oxytetracycline Hydrochloride (2000)
    Springer
    Microchimica acta 135 (2000), S. 97-104 
    Details
    ISSN: 1436-5073
    Keywords: Key words: Oxytetracycline hydrochloride; ion-selective electrodes; potentiometry; coated wire; phosphotungstate; phosphomolybdate, tetraphenylborate.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract.  Oxytetracycline hydrochloride-selective electrodes of both the coated wire and the conventional polymer membrane types based on oxytetracyclinium phosphotungstate and phosphomolybdate have been prepared. A Nernstian response is shown by these electrodes within 1.0×10−6–1.0×10−2 M concentration ranges depending on the type of electrode. The response is unaffected by the change of pH over the range 4–11. The standard electrode potentials, E°, were determined at different temperatures and used to calculate the isothermal temperature coefficients of the electrodes. The electrodes show good selectivity to oxytetracycline hydrochloride with respect to many inorganic cations, sugars and amino-acids. Oxytetracycline hydrochloride is determined successfully in pure solutions and in pharmaceutical preparations using calibration by standard addition and potentiometric titration. A regeneration process for the exhausted electrodes has been developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s006040070024
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  • 9
    Electronic Resource
    Electronic Resource
    PVC Membrane electrode for trinitrobenzenesulfonate and its use for indirect determination of amino acids (1997)
    Springer
    Microchimica acta 126 (1997), S. 319-324 
    Details
    ISSN: 1436-5073
    Keywords: trinitrobenzenesulfonic acid ; amino acids ; ion-selective electrode ; cetyltrimethylammonium bromide ; urine analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A PVC membrane electrode of the conventional type was prepared which is selective for trinitrobenzenesulfonate (TNBS−). It showed a rapid Nernstian response within the TNBS− concentration range 1.0 × 10−5 to 1.0 × 10−2 M at 25 ± 0.1°C. The electrode was selective, precise (RSD 〈 0.87% for TNBS− and 〈 1.32% for amino acids) and usable within the pH range 2.5–12. The standard electrode potentials,E°, were determined at different temperatures and used to calculate the isothermal temperature coefficient of the cell. Selectivity coefficients for numerous compounds are given. The electrode has been used for the direct determination of trinitrobenzenesulfonic acid in aqueous solutions either by the standard additions method or by potentiometric titration against cetyltrimethylammonium bromide (CTABr) at pH 7. The electrode has been also applied successfully for the indirect microdetermination of neutral, acidic and basic amino acids separately, and as binary or ternary mixtures of neutral amino-acids. Total amino acids were determined in urine samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242339
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  • 10
    Electronic Resource
    Electronic Resource
    The determination of phosphonate base scale inhibitors in brines by plasma spectrometry (1992)
    Springer
    Microchimica acta 109 (1992), S. 201-209 
    Details
    ISSN: 1436-5073
    Keywords: phosphonate base scale inhibitor ; brine ; direct current plasma ; inductively coupled plasma atomic emission spectrometry ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The determination of phosphonate base scale inhibitors in brines by direct current plasma (DCP) and inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The first method is based on a direct nebulization of the brine samples and plasma using the phosphorus line at 213.618 nm. The second method involves extraction of phosphorus as phospho-antimonyl molybdate complex into methylisobutyl ketone (MIBK) phase and analysis of the extract for molybdenum using the Mo 313.260 nm line. Comparison between the proposed methods and an established recommended method [1] shows excellent agreement between the results in addition to the sensitivity and ease of automation provided by AES.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242475
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