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Liquid chromatographic determination of nitrilotriacetic acid, ethylenediaminetetraacetic acid, and related aminopolycarboxylic acids using an amperometric detector

Journal Article · · Anal. Chem.; (United States)
DOI:https://doi.org/10.1021/ac00155a005· OSTI ID:5523524
An amperometric detector employing a carbon-paste electrode is used to determine aminopolycarboxylic acids, including nitrilotriacetic acid (NTA) to determine aminopolycarboxylic acids, including nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA), after liquid chromatographic separation on a reversed-phase column with an aqueous trichloroacetic acid mobile phase at pH lower than 2. The aminopolycarboxylic acids are directly oxidized at the detector electrode without involving an intermediate species. Glycine, iminodiacetic acid, common amino acids, citric acid, and fulvic acids do not interfere with the determination of NTA and EDTA. The low mobile-phase pH limits interference from metal ions in natural waters. Where such interference occurs, a stronger chelating reagent (e.g. diethylenetriaminepentaacetic acid (DPTA) can be used to suppress it. NTA and EDTA in aqueous samples, including waste water treatment plant influent and effluent, can be determined without prior sample preparation. The minimum detectable amounts are 0.1 ppm for NTA and 0.15 ppm for EDTA with a precision of less than 7% relative standard deviation.
Research Organization:
Univ. of Maryland, College Park
OSTI ID:
5523524
Journal Information:
Anal. Chem.; (United States), Journal Name: Anal. Chem.; (United States) Vol. 60:4; ISSN ANCHA
Country of Publication:
United States
Language:
English