ABSTRACT
OBJECTIVE: To evaluate the suitability of two pretreatment methods, the nitric acid digestion method and the elution method, and two measurement modes of inductively coupled plasma-mass spectrometry(ICP-MS), the No gas mode and the helium collision(He) mode, for the determination of lithium and its compounds in the workplace air. METHODS: We collected lithium and its compounds in the air of the workplace using the microporous filter membrane, and two pretreatment methods, the nitric acid digestion and elution methods were used for processing, and measured with the No gas mode and the He mode of ICP-MS. RESULTS: The good linearity range of lithium concentration in No gas mode and He mode of ICP-MS method was 0.00-500.00 μg/L, and the correlation coefficient was 0.999. The detection limit and the lower limit of quantification of lithium were 0.04 and 0.13 μg/L respectively in the No gas mode. In He gas mode: they were 0.12 and 0.39 μg/L respectively. Using the nitric acid digestion method for pre-treatment, the recovery rate of lithium addition was 96.9%-104.9%; the within-run and the between-run relative standard deviations were 3.3%-5.0% and 2.9%-5.3% respectively. Using the elution method for pre-treatment, the recovery rate of lithium addition was 97.6%-102.1%; the within-run and the between-run relative standard deviation were 3.3%-4.6% and 3.4%-4.8%, respectively. The sample could be stored at room temperature for at least 14 days. CONCLUSION: The ICP-MS method can be used as a new technology for detecting lithium and its compounds in the air of workplace. It is recommended that the elution method and the No gas mode be the first choice when measuring lithium and its compounds.