Abstract:Abstract To establish a direct dilution-inductively coupled plasma mass spectrometry method for measuring total iodine in saliva. This method eliminates the need for pretreatment such as strong oxidants or high-temperature thermal digestion of saliva samples. By simply diluting the samples with a diluent (a mixed solution of 0.1% ethanolamine, 1.0% ethanol, 1.0 g/L ammonium chloride, and 2 g/L ascorbic acid) and injecting them directly, it enables rapid and accurate determination of total iodine in saliva without the use of highly toxic arsenic trioxide reagents. Within the iodine concentration range of 0 μg/L to 300 μg/L, the standard curve exhibits excellent linearity with correlation coefficients exceeding 0.999. The method's minimum quantification limit is 0.96 μg/L (with a sampling volume of 0.20 mL), and the intra- and inter-batch relative standard deviations (RSDs) for sample detection range from 0.4% to 1.1% and 0.7% to 1.3%, respectively, both below 10%. The spiked recovery rates for various saliva samples range from 97.1% to 104.6%, with an overall average recovery of 101.1%. The method demonstrates excellent anti-interference capability, with relative deviations caused by endogenous interferants within a certain range ranging from -4.4% to -0.8%, and absolute values of relative deviations all <10%. When compared with the arsenic-cerium spectrophotometry method, there was no statistically significant difference in results. This method is suitable for rapid quantitative determination of saliva iodine in iodine nutrition monitoring by disease prevention and control departments and medical institutions at all levels in China.