Online Arsenic Species Separation and Analysis of Arsenite, Arsenate, Monomethylarsenate, Dimethylarsonate and Arsenocholine Using Liquid Chromatography and Hydride Generation Atomic Fluorescence Spectrometry

Aims: The purpose of this research was to establish a five-arsenic-species separation and analysis method including arsenite [As(III)], arsenate [As(V)], monomethylarsonate (MMA), dimethylarsonate (DMA) and arsenocholine (AsC) in water sample by liquid chromatography with hydride generation atomic fluorescence spectrometry (LC-HG-AFS).
Study Design: The Successful separation and detection for the five arsenic species can be achieved through changing the chromatographic columns and adjusting the compositions of mobile phase.
Place and Duration of Study: Study in the laboratory of College of Marine Science and Engineering at Tianjin University of Science & Technology between March 2014 and September 2014.
Methodology: Firstly the effect of anion exchange chromatography was compared with that of reversed-phase ion-pair chromatography for separating the five arsenic species. Then reversed-phase ion-pair chromatography was selected in the next step because of its universality for separating these arsenic species by adjusting mobile phase.
Results: Effective separation was achieved within 10 min for all the five arsenic species by a single reversed-phase ion-pair chromatographic column eluted with 1 mmol/L diammonium hydrogen phosphate buffer [(NH4)2HPO4] (pH=6.00) + 1% (v/v) CH3OH + 5 mmol/L tetrabutyl ammonium bromide (TBAB). The concentration of arsenic compounds were determined by peak height. And the concentration of AsC, As(III), As(V), MMA, DMA were 250 μg/L, 100 μg/L, 100 μg/L, 100 μg/L, 100 μg/L respectively in this experiment.
Conclusion: The five arsenic species can be effectively separated and detected by hyphenated techniques (LC-HG-AFS).