To compare the effects of different sample pretreatment methods on the determination of six elements [iron (Fe),copper (Cu), manganese (Mn), nickel (Ni), zinc (Zn), and strontium (Sr)] in whole blood by ICP-MS, so as to optimize the pretreatment process of whole blood samples and improve the accuracy and reliability of detection.

Appropriate amounts of whole blood samples were taken. The collision mode was applied to eliminate interference, and quality control samples were used for quality control. The detection effects of sample pretreatment methods including microwave digestion, protein precipitation with 5% nitric acid followed by centrifugation, direct dilution with 0.1% HNO₃ + 0.01% Triton X-100, and dilution with 0.1% HNO₃ + 0.01% Triton X-100 followed by centrifugation were compared.

When the samples were pretreated by protein precipitation with 5% nitric acid followed by centrifugation, the detection results of iron, manganese, nickel, zinc and strontium in the centrifuged supernatant were found to be low, and the effects on iron, manganese and nickel were the most significant. In addition, when the HNO₃ concentration was 0.2% - 1% (V/V), the measured contents of iron, manganese, nickel, zinc and strontium after dilution followed by centrifugation were all lower than those by direct dilution method and microwave digestion method. When the HNO₃ concentration was 0.1% (V/V),there was no significant difference between the results of direct dilution and dilution followed by centrifugation of the six elements compared with the microwave digestion method. Finally, dilution with 0.1% HNO₃ + 0.01% Triton X-100 (V/V) followed by centrifugation was used as the pretreatment condition. The method detection limits of the six elements were between 0.10 μg/L and 0.24 mg/L, the correlation coefficients r was all greater than 0.999, and the measured values of the quality control samples were consistent with the standard reference values.

Compared with other pretreatment methods, using 0.1% HNO3 +0.01% Triton X-100 (V/V) dilution followed by centrifugation as the pretreatment condition is simple, fast and accurate, and can be applied to the determination of iron, copper, manganese, nickel, zinc and strontium in whole blood.