cen:proj:76790

Algae and algae products —Determination of inorganic arsenic in algae and algae products by anion-exchange (HPLC-ICP-MS) cen:proj:76790

Scope

This document describes a method for the determination of inorganic arsenic in algae by anion-exchange HPLC-ICP-MS following water bath extraction. Inorganic arsenic consists of arsenite, As(III) and arsenate, As(V).

A representative test portion of the sample is treated with a diluted nitric acid and hydrogen peroxide solution in a heated water bath. Hereby the arsenic species are extracted into solution and As(III) is oxidised to As(V). The inorganic arsenic is selectively separated from other arsenic compounds using anion exchange HPLC (High Performance Liquid Chromatography) coupled on-line to the element-specific detector ICP-MS (Inductively Coupled Plasma Mass Spectrometry) for the determination of the mass fraction of inorganic arsenic. External calibration with solvent matrix-matched standards is used for quantification of the amount of inorganic arsenic.

The method is based on method EN16802: Inorganic arsenic in food of plant and marine origin by HPLC-ICPMS, but covers more algae species. The present AsSugar species in certain algae can cause As peaks which might overlap with the As peaks related to the inorganic As. The current method includes a gradient elution method with quality criteria to ensure a correct identification of the inorganic arsenic.