Speciation of AsIII and AsV in fruit juices by dispersive liquid–liquid microextraction and hydride generation-atomic fluorescence spectrometry

Abstract

A sensitive method was developed to speciate and quantify AsIII and AsV in fruit juices. At pH 3.0, AsIII and ammonium pyrrolidine dithiocarbamate (APDC) formed a complex, which was extracted into CCl4 by dispersive liquid–liquid microextraction (DLLME) and subsequently quantified by hydride generation-atomic fluorescence spectrometry (HG-AFS). After AsV was reduced by thiosulphate at pH 1.7–1.8, total inorganic arsenic (iAs) was determined following the same protocol and AsV was calculated from the difference. Interference from methylarsonic acid (MMA) was managed at <10% by controlling the pH of the reduction reaction. This procedure achieved 1.2μgL−1 limit of detection (3σ) and 92–102% recovery at 10μgL−1, and is applicable to most fruit juices except certain pear juice that may contain considerable MMA.