Abstract
Dried blood spot (DBS) sampling is a valuable method in clinical analysis due to its minimally invasive nature, reduced sample volume requirements, and simple storage conditions. DBS analysis is of specific interest in assessing exposure to medically relevant heavy metals, such as cadmium (Cd), mercury (Hg), and lead (Pb). However, the limited sample volume presents analytical challenges, particularly for low-concentration analytes, necessitating a highly sensitive and selective detection method. Inductively coupled plasma-mass spectrometry (ICP-MS) is the predominant technique for DBS heavy metal analysis, yet the complexity of the blood matrix often complicates direct analysis. After extraction of the sample from the substrate via acid digestion or ashing, chromatographic separations and additional pre-treatment steps are frequently required before MS detection, resulting in time-consuming workflows. To address these issues, we present an alternative DBS analysis approach utilizing the Advion Plate Express microextraction device (μEx-ICP-MS) for direct sampling with minimal sample preparation. This method enables rapid (-1 detection limits), and multi-element profiling of DBS substrates. In this approach, a ∼2 × 4 mm region of the DBS sample is exposed to an extraction solvent, efficiently removing adsorbed species with direct delivery to the ICP nebulizer. The use of aqueous calibration standards for Cd, Hg, and Pb in real human blood samples provides matrix matched quantification. Additionally, studies examining sample extraction reproducibility and metal recovery from standard samples are presented. This method offers a streamlined, accessible approach for microextraction from DBS substrates and elemental detection in clinical analyses.