ISSN:
1436-5073
Keywords:
ammonia-nitrogen
;
preconcentration by filter
;
indothymol
;
spectrophotometry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Ammonia-nitrogen, in the range 0.06 to 2 μg in 20 ml of water sample, is treated with hypochlorite and thymol to form an intensely blue anionic dye called indothymol. The indothymol is collected on a glass-fiber filter as the ion-pair with benzyldimethyltetradecylammonium ion. The indothymol collected on the filter is dissolved in a small volume of dimethylformamide (DMF) and the absorbance due to the indothymol is measured at 675 nm against the reagent blank. An unexpectedly high sensitivity was obtained because of the increased molar absorptivity of indothymol in DMF (3.2 × 104 l mol−1 cm−1, λmax = 675 nm), approximately 3 times larger than that in water (1.16 × 104 l mol−1 cm−1, λmax = 660 nm). The detection limit, defined as three times the standard deviation of the blank, is better than 1 μg 1−1 of ammonia-nitrogen with 5-fold preconcentration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01242704
Permalink