A Simple Microwave-Assisted Method for the Determination of Boron, Sulfur, Bromine, Chlorine, and Iodine in Whole Blood by ICP-QQQ for Biomonitoring Applications

The simultaneous determination of non-metal elements in whole blood remains analytically challenging because of the complex biological matrix and the wide concentration range. This study describes a simple microwave-assisted alkaline extraction method for the determination of boron, sulfur, bromine, chlorine and iodine in human whole blood by triple quadrupole inductively coupled plasma mass spectrometry. The proposed procedure requires only 100 µL of whole blood, which is processed directly in a disposable 5 mL polypropylene vial that is subsequently introduced into the autosampler, eliminating sample transfer steps and reducing handling and contamination risks. A single instrumental configuration was applied for all analytes using oxygen as the reaction/collision gas, while the formation of 35Cl18O+ was deliberately employed to attenuate the chlorine signal, allowing the simultaneous determination of major- and trace-level elements without detector saturation. The proposed method showed satisfactory precision (RSD < 15%), agreement with reference and assigned values, spike recoveries, limited effects of matrix load, and analytical solution stability for at least 24 h at room temperature. Limit of detection of whole-blood were 6.03 µg L−1 for boron, 0.134 mg L−1 for sulfur, 24.4 mg L−1 for chlorine, 6.26 µg L−1 for bromine, and 0.944 µg L−1 for iodine, providing suitable sensitivity for concentrations typically encountered in human whole blood. Overall, the method provides a simple, robust, and high-throughput approach for routine biomonitoring of non-metals in whole blood.