Objective To establish a wet digestion method for the determination of tin in blood by atomic fluorescence spectrometry.
Methods One mL whole blood was collected and mixed with nitric acid, hydrochloric acid, sulfuric acid and hydrogen peroxide in different proportions. The blood sample was digested at 90 ℃ by graphite digestion apparatus. After digestion, 1 mL thiourea ascorbic acid solution was added to mask nickel, iron, arsenic, selenium and other interfering ions. The volume was made up to 10 mL with 4% hydrochloric acid solution. The tin concentration was determined by hydride generation atomic fluorescence spectrometry.
Results Based on the results of different digestion combinations, The optimized wet digestion method was to add 2 mL hydrogen peroxide to 2 mL nitric acid, and then digested the sample at 90 ℃ for 1 h.Under this condition, the linear range of tin in blood was 4.00 - 200.00 g/L, the correlation coefficient was 0.999 5;the detection limit was 0.20 g/L, the recovery was 99.76% - 105.72%, and the RSD was 0.21% - 2.59%. The sample could be stored for 7 days at 4 ℃.
Conclusions This wet digestion method can achieve the sample complete digestion, with minimum loss of target analyte and low matrix interference, and it also has good accuracy and precision. What's more, the digestion instrument used in this method is affordable and widely used in the grass-roots laboratories, which is suitable for the determination of tin concentration in human blood.
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