Efficient extraction and analysis method for lead-containing nanoparticles in complex biological samples to eliminate "false" interferences by using SP-ICP-MS.

Metal-containing nanoparticles (MNPs) ubiquitously exist in the environment and organisms, playing distinct roles in the fate and toxicity of metals. However, the extraction and analysis of the MNPs in biological samples is still a great challenge and the interferences of other metal species and complex matrices remains unclear. In this work, we established a method for efficient extraction and accurate analysis of MNPs in biological samples to eliminate the interference caused by metal ions and biological matrices based on the alkali extraction and single particle mode inductively coupled plasma mass spectrometry (SP-ICP-MS). Obvious interference signals of lead-containing nanoparticles (PbNPs) were found in various biological matrices (liver, brain, bile, intestine, stomach), causing false positive results or overestimation of PbNPs. Then, a novel strategy using EDTA and ultrasonic during the TMAH extraction process were proposed to successfully eliminate the interferences due to the strong and competitively binding of EDTA to Pb ions, which was identified as ionic signals in SP-ICP-MS and resulted in the elimination of interferences. Finally, this method was successfully applied for the extraction, characterization and quantification of PbNPs in different biological tissues collected near a power plant, revealing the occurrence of PbNPs in stomach, intestine and liver tissues and indicating their oral exposure and potential translocation. This method could be universally applied for the efficient extraction and accurate analysis of MNPs in biological samples and thus provided a reliable and powerful tool for the investigation of the occurrence, fate and toxicity of MNPs in environmental and organisms.