Arsenic (As) toxicity is a major public health concern due to its widespread environmental presence and association with severe health outcomes. Assessing As exposure is therefore essential for understanding its health risks. Determination of urinary As is the most widely used measure for recent As exposures due to sample availability and that As is primarily excreted in urine within 48 hours. However, the toxicity of As is highly dependant on its chemical form. Inorganic arsenic species, arsenite (As(III)) and arsenate (As(V)), are highly toxic and classified as Group 1 carcinogens. Methylated metabolites, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), are less toxic but still pose health risks, while organic arsenic compounds, such as arsenobetaine (AsB) and arsenocholine (AsC), commonly found in seafood, are considered non-toxic.

To better understand As exposures within a population a pilot biomonitoring project was undertaken to provide insight into the variability in total levels of total As and 6 different As species. During sample storage As species can be converted, this is largely controlled by factors such as storage conditions, storage duration and salt profile of the sample. As part of this work, the later is being investigated [1]. For methods to be appropriate for biomonitoring applications a robust, rapid and reliable method is required. To achieve this, we established a rapid and automated method for urinary arsenic speciation using a prepFAST IC system (Elemental Scientific Inc.) coupled with ICP-MS. This method enables the high-throughput separation and quantification of six arsenic species (AsB, DMA, MMA, AsC, As(III), and As(V)) in under two minutes, figure 1 [2]. The ability to rapidly and accurately differentiate toxicologically relevant arsenic species enhances biomonitoring applications by improving exposure assessment, informing risk evaluations, and strengthening public health strategies.