Summary
This 2026 technical report describes the development, challenges, and post-implementation experience of an HPLC-ICP-MS method for urinary arsenic speciation in a clinical laboratory setting. The study characterises the separation and quantification of arsenite As(III), arsenate As(V), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in urine, and identifies two previously uncharacterised unknown arsenic peaks encountered in some clinical samples during routine operation. The paper is primarily an analytical methods reference for clinical and biomonitoring laboratories.
Key numbers
- Target analytes: iAs(III), iAs(V), MMA, DMA in urine
- Two unidentified species detected in a subset of clinical urine samples; chromatographic retention times documented
- Method performance: validated accuracy, precision, and linearity for the four target analytes (specific values in paper)
Methods
HPLC-ICP-MS using an anion-exchange or mixed-mode column (specific column type per paper). Urinary matrix; acid digestion/dilution for sample preparation. Post-implementation experience covers approximately 2 years of clinical operation.
Implications
The identification of two unknown arsenic species in routine clinical urines is methodologically significant: unaccounted-for species contribute to mass balance discrepancies when summing iAs+MMA+DMA and comparing to total urinary arsenic by ICP-MS. This finding, paralleled by Cheng et al. 2026 (HEALS cohort), suggests that standard four-analyte urinary arsenic speciation panels may not capture all arsenic species in some populations. For biomonitoring studies that use speciated urinary arsenic as an exposure biomarker, the presence of uncharacterised species is a source of residual uncertainty.
Related evidence
Update history
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