Speciation Analysis of Arsenic in Honey

Recently, researchers from Poland unveiled groundbreaking findings on arsenic concentration in honey samples collected from Poland and Ukraine, a pioneering endeavour in this domain. They devised a method to discern five arsenic species, including the highly toxic As(III), As(V), dimethylarsinic acid (DMA), methylarsonic acid (MMA), and the innocuous arsenobetain.

Their innovative separation technique, leveraging Ion Chromatography (IC) with gradient elution, coupled an anion exchange column with an anion–cation exchange guard column to enhance separation efficacy. The mobile phase, comprising ammonium nitrate and methanol, underwent pH adjustment with ammonia.

Honey samples underwent dilution with water and heated to 90°C for an hour to extract arsenic species, yielding high recovery values. Remarkably, total arsenic concentrations indicated the efficacy of water extraction.

Achieving separation of the five arsenic species within a concise timeframe of less than 14 minutes, the study unearthed predominantly inorganic arsenic species with varying As(III)/As(V) ratios contingent on the sampling region. Notably, MMA was solely detected in Ukrainian honey samples, while DMA featured in only one Polish honey sample.

However, the authors acknowledge their analysis solely addressed water-soluble arsenic, precluding direct comparison with existing results, given the absence of prior speciation data.

An important consideration arises regarding the susceptibility of As(III) to oxidation to As(V) during sample preparation, particularly under elevated temperatures. Thus, the reliability of As(III)/As(V) ratios in honey samples post-heating to 80°C for an hour warrants scrutiny. Regrettably, the authors did not explore species stability under the conditions of their sample preparation, leaving this aspect unaddressed.

The original publication

Related EVISA Resources