Application of Volumetric Absorptive Microsampling (VAMS) for the simultaneous determination of cadmium and lead in blood

Background Cadmium (Cd) and lead (Pb) are environmental pollutants with toxic effects on humans. This study evaluates the applicability of Volumetric Absorptive Microsampling (VAMS) as an alternative sampling method for the simultaneous biomonitoring of Cd and Pb in blood of humans without occupational exposure. Methods VAMS and blood samples were collected from 87 participants. Of these, 60 VAMS sets were used as supplied by the manufacturer and 27 VAMS sets were washed with 0.5% nitric acid before the sampling to reduce the background contamination. The samples were extracted (VAMS) or diluted (venous blood) with 0.5% nitric acid prior to analysis by ICP-MS. Results Mean recovery rates for Cd and Pb were 104% and 100% using untreated VAMS, and 116% and 110% with prewashed VAMS, respectively. A strong correlation was found for venous blood and unwashed VAMS samples (Cd ρ = 0.85; Pb ρ = 0.94). The correlation was improved when pre-washed material was used (Cd ρ = 0.91; Pb ρ = 0.97). Without washing, the limits of quantification (LOQ) were 0.55 µg/l for Cd and 17.17 µg/l Pb. Washing of VAMS devices lead to a significant reduction of the contamination, especially for Pb. The resulting LOQ were 0.46 µg/l for Cd and 2.19 µg/l for Pb. Conclusion Despite challenges like the background contamination, VAMS is a promising alternative sampling method for human biomonitoring of Cd and Pb in blood. This study also demonstrates the benefits of washing VAMS to reduce background contamination.