Application of volumetric absorptive microsampling (VAMS) for the simultaneous determination of cadmium and lead in blood

Cadmium (Cd) and lead (Pb) are toxic elements. This study evaluates the applicability of volumetric absorptive microsampling (VAMS) as an alternative sampling method for biomonitoring of Cd and Pb in human blood. VAMS and blood samples were collected from 60 participants using untreated VAMS. Furthermore, samples from additional 27 participants were collected using VAMS pre-cleaned with 0.5% (v/v) nitric acid to reduce background levels in VAMS and improve performance. All samples were extracted (VAMS) or diluted (venous blood) with 0.5% (v/v) nitric acid prior to analysis by ICP-MS. For untreated VAMS, geometric mean (GM) recovery was 106.2% for Cd and 102.8% for Pb. For pre-cleaned VAMS, GM recovery was 117.2% for Cd and 104.6% for Pb. A strong correlation (Spearman Rho) between both methods was found (Cd, ρ = 0.84; Pb, ρ = 0.93). Correlation improved (Cd, ρ = 0.91; Pb, ρ = 0.98) for pre-cleaned VAMS. For untreated VAMS, the limits of quantification (LOQ) were 0.42 µg/l for Cd and 15.3 µg/l Pb. Pre-cleaning of VAMS led to a 90% background reduction for Pb (0.35 µg/l vs 3.61 µg/l). Background of Cd was unaffected by pre-cleaning (0.05 µg/l vs 0.07 µg/l). LOQs for pre-cleaned VAMS were 0.45 µg/l for Cd and 2.10 µg/l for Pb. Despite challenges like the background, VAMS is a promising alternative sampling method for human biomonitoring of Cd and Pb in blood. This study demonstrates the benefits of washing VAMS to reduce background.