Quantitative determination of Cd in single hair strands using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)

ABSTRACT This study explores the use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for the direct quantification of cadmium in human hair, addressing the demand for rapid, spatially resolved, and minimally destructive biomonitoring methods. Cadmium, a toxic heavy metal associated with renal and metabolic disorders, is typically measured using techniques that require extensive sample preparation, potentially compromising temporal and spatial exposure data. This work fills the gap in validated LA-ICP-MS hair analysis protocols by implementing matrix-matched calibration and validating the method against solution nebulization ICP-MS. The aim was to develop a robust, high-resolution technique capable of accurately quantifying cadmium across a broad concentration range. Calibration curves were prepared using certified reference materials, and method performance was evaluated through precision, accuracy, reproducibility, and depth-profile analysis. The method showed excellent linearity (R2 > 0.999), with cadmium levels in environmentally exposed individuals exceeding EPA thresholds by up to 1100%, indicating elevated renal toxicity risk. Spatial mapping revealed distinct cadmium peaks linked to occupational and environmental exposure events, while zinc and sulfur served as stable internal standards, enhancing reliability. These results position LA-ICP-MS as a powerful alternative to conventional methods, with future work focusing on population studies, and isotopic tracing for source attribution.