Iron Single-Atom Catalyst Boosting Dried Blood Spots Digestion for High-Throughput Detection of Arsenic and Cadmium

Herein, a novel Fenton-like digestion strategy has been developed for undiluted, rapid, and high-throughput digestion of DBS samples. The key of this strategy is the development of a blood collection card loaded with iron single-atom catalysts (Fe-SACs). Then, approximately 40 μL of blood sample was dripped onto the Fe-SACs blood collection card and digested with tens of microliters of H2O2 at 75 °C. Remarkably, digestion of the DBS sample can be achieved within 5 min. It is proposed that the Fe-SACs with their high atomic utilization efficiency, are uniformly immobilized on the paper substrate, thereby increasing the contact area with blood and significantly enhancing sample digestion efficiency. Furthermore, it is worth noting that the issues of intense reaction and severe matrix interference associated with the conventional Fenton-like digestion of whole blood are effectively alleviated by performing the digestion process directly on the paper. The preparation of DBS samples and their Fe-SACs-based Fenton-like digestion can be carried out in a 24-well plate, enabling a theoretical digestion of up to 288 samples per hour, greatly improving sample digestion throughput. The practicality of the developed method was evaluated by analyzing a series of real blood samples. The results showed good agreement with those obtained using conventional wet digestion followed by inductively coupled plasma mass spectrometry (ICP-MS), indicating this strategy retains a good potential for the rapid and efficient digestion of whole blood samples.