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.
ABSTRACT
OBJECTIVE: To establish a methodology for determining indium in human whole blood,serum and urine by inductively coupled plasma-mass spectrometry( ICP-MS). METHODS: The whole blood,serum and urine samples were diluted 10 times in 0. 01%( mass fraction) Triton X-100 plus 0. 50%( mass fraction) nitric acid solution,and the indium level was determined by ICP-MS. Rhodium standard solution was used as the internal standard control. RESULTS: The working curve obtained from measurement of whole blood,serum and urine of normal individuals was compared to the standard curve and showed no significant difference in quantitative analysis( P > 0. 05). The linearity range of indium concentration in whole blood,serum and urine was 0. 000-20. 000 μg / L,and all the correlation coefficients were greater than 0. 999 with a detection limit of 0. 144 μg / L. The recovery rates of whole blood,serum and urine were 87. 90%-95. 92%,91. 50%-94. 20% and 90. 40%-96. 57%,respectively. The relative standard deviations( RSDs) of within-run precision were 3. 81%-7. 05%,3. 75%-5. 90% and 4. 31%-6. 62%,respectively. The RSDs of between-run precision were 2. 90%-7. 10%,3. 80%-5. 92% and 4. 16%-5. 94%,respectively. Samples could be stored for at least 14 days under the temperature of- 20 ℃. The indium in whole blood,serum and urine of workers occupationally exposed to indium( exposure group,135 person-time) and control group workers( 120 person-time) were examined. Indium was detected for 17 person-time in whole blood and serum in the exposure group with a detection rate of 1. 26%. Indium was not detected in urine samples in exposure group. It was not detected in all samples in control group. CONCLUSION: This methodology has features of simple operation,high accuracy and good precision,which is suitable for the accurate quantitative analysis of indium in biological samples.