ISSN:
1612-1112
Keywords:
Column liquid chromatography
;
Nitrites
;
Fluorescence
;
Precolumn derivatization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Summary A rapid, simple, and sensitive method is described for determination of nitrites in water. Nitrite (NO2−) ions react with coumarin 120® (4-methyl-7-aminocoumarin) in sulfuric acid medium to give the corresponding 7-diazo compound. After hydrolysis, this latter yields (95%) the highly fluorescent 4-methyl-7-hydroxycoumarin (4-methylumbelliferone) which is fluorimetrically detected at 380 nm after excitation at 325 nm. In order to avoid interference from both excess coumarin 120® and the trace amounts of 4-methylumbelliferone which occurs in coumarin 120® as an impurity, use of HPLC is mandatory; a satisfactory separation is obtained on a cyano stationary phase with apolar hexane-isopropanol (95∶5, v/v) as eluent. Under these conditions, linearity of response is obtained from 1 to 30 μg.L−1 of NO2−; the limit of detection is 0.5 μg.L−1. The repeatability and reproducibility, expressed as RSD %, are 2.5 and 4.7 % respectively, for n=6 and 5 μg.L−, analytical characteristics which demonstrate the reliability of the proposed method.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02263837
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