Effect of acid-base diluent on the determination of 19 elements in whole blood by inductively coupled plasma mass spectrometry / 中华检验医学杂志

ABSTRACT

Objective:To analyze the effect of acidic or alkaline diluents of the direct dilution method on the results of multiple elements measurement in whole blood by inductively coupled plasma mass spectrometry (ICP-MS) and to explore the possibility whether the two diluents can be substituted for each other in elemental measurement results.Methods:A total of 162 human whole blood samples collected from the National Human Biomonitoring Programme in August 2018 were used for dilution with different diluents followed by centrifugation, then the supernatants of the samples were measured by ICP-MS. The methodological characteristics of the two pre-treatment methods including acidic diluent (0.1% nitric acid+0.01% tralatone solution) and alkaline diluent (0.05% n-butanol+0.01% tralatone+1% ammonium hydroxide solution) were evaluated separately. Spearman correlation coefficient analysis was used for the correlation of 19 elements results in whole blood measured by 2 diluents, then, Passing-Bablok linear regression and Bland-Altman plots were used to evaluate the consistency of the 19 elements results in 162 whole blood samples between the two diluents.Results:The methodological data of 19 elements using the two diluents were good, with the limits of quantification (LOQ) of the 19 elements were 0.1-15.8 μg/L for acidic diluents and 0.3-19.2 μg/L for alkaline diluents, and the linear correlation coefficients of the standard curves of the 19 elements using the acidic and alkaline diluents were all≥0.995. Except for strontium, cadmium, tin, and thallium, the recovery percents of the 19 elements were all in the range of 80%-120%, and for all elements the total coefficients of variation of within-and between-run in the acidic and alkaline diluents were 0.5%-12.4%. The correlation coefficients of the two diluents for the measured values of chromium, manganese, cobalt, zinc, copper, arsenic, selenium, strontium, molybdenum, silver, cadmium, antimony, barium, mercury, and lead were relatively strong ( R2>0.8), while the correlation coefficients of vanadium, nickel, tin, and thallium were relatively weak ( R2<0.8). For the vanadium, cadmium, tin, barium, and mercury, 95% confidence intervals of slopes were<1. The 95% confidence intervals of intercepts of chromium, nickel, arsenic, silver, barium, and mercury contain point 0. The Bland-Altman plot showed that vanadium, chromium, arsenic, strontium, silver, cadmium, tin, and mercury have good consistency in using acidic and alkaline diluents. Conclusion:The results of the mean values measured with the 2 diluents differed among different elements and could not be completely substituted.