Determination of Arsenic Species in Beverages by HPLC-ICP-MS Application Note · PlasmaQuant MS

Introduction

The species or chemical form of elements determines their mobility, bioavailability and toxicity. Liquid chromatography or ion chromatography allow a separation of these species. The subsequent detection by mass spectrometry provides a highly sensitive method for their quantification. Hence, LC-ICP-MS and IC-ICP-MS provide an essential tool for assessing benefits and/or risks of elements present in the sample.

An element can be essential and toxic just based on the oxidation state or compound in which it occurs. Thus, food samples like seafish, rice or chocolate, apple juice and other foods and beverages are controlled by LC-ICP-MS for arsenic, selenium or chromium species present.

Arsenic speciation plays an important role in the characterization of food samples since it is absorbed from the soil into food plants like rice or apple and orange trees. Mostly accumulated in the fruit, the related products need to be characterized for their arsenic content. The inorganic trivalent arsenic (AsIII) and pentavalent arsenic (AsV) for example are the most toxic arsenic forms, whereas the organic monomethyl arsenic (MMA) and dimethyl arsenic (DMA) have significantly reduced toxicities, while arsenobetaine (AsB) is not toxic at all.

The application note describes a gradient method for the PQ LC HPLC system developed to separate five arsenic species with special attention to well separated chromatographic signals in shortest time. To test the method‘s applicability for real samples, commercially available apple juice and orange juice samples were analyzed.