Enzyme-assisted extraction and liquid chromatography-inductively coupled plasma mass spectrometry for the determination of arsenic species in fish.

ABSTRACT

A sensitive, simple and rapid method for the simultaneous determination of eleven arsenic species has been developed. A high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) technique was used for the analysis of eleven arsenic species in less than 17 min. Different extraction solutions were explored and the recovery results using water and aqueous acidic solvents, aqueous organic solvents and enzymes showed that 40 mg protease with 0.75 mL 0.5% hydrochloric acid (v/v) as the extraction agent gave the best experimental results. Species separation with ammonium carbonate solution as the mobile phase was conducted on an anion-exchange chromatographic column using gradient elution. The column temperature was 20 °C and kinetic energy discrimination (KED) was employed to eliminate spectral interference. The use of KED mode effectively removed interference from 75ArCl. The detection limit (LD) of the method was in the range of 0.11-0.59 µg kg-1. Repeatability values obtained for spiked real fish samples were in the range of 1.1%-7.6%. Accuracy was calculated based on the analysis of spiked real fish samples at five concentration levels. Obtained recoveries were 91%-106%. The validated method was used in a pilot study to analyze real samples of fish, the organic arsenic especially AsB was the major arsenic specie present in the analyzed samples, only trace amount of inorganic arsenic were detected. The analytical method should improve the assessment of human exposure associated with arsenic intake from fish.