Determination of Cadmium Element in Poisoned Corpse by Inductively Coupled Plasma Mass Spectrometry with Standard Addition Method

In order to research the distribution of cadmium in the poisoned corpse, a method for the determination of cadmium in poisoned corpse by inductively coupled plasma mass spectrometry (ICP-MS) with standard addition method was proposed. The biological fluids (including whole heart blood, bile and pleural effusion) and solid tissues (including heart, spleen, lung, kidney, brain and stomach) from cadmium-poisoned corpse were collected. The six biological fluids or solid tissues of 250 μL each were taken, and cadmium standard solution series with 6 concentration levels (indium as the internal standard) and nitric acid were added into each of the above samples. The samples were digested at the highest digestion temperature of 170 ℃ for 10 min, and the digested solutions were made up to 10 mL by 2% (φ) nitric acid solution. ICP-MS was used for the determination, with the content of cadmium as the horizontal coordinate and the signal strength ratio of cadmium to indium as the vertical coordinate for linear regression. The absolute value of the intersection between the extension line of the working curve and the x-axis was the content of cadmium in the sample. It was shown that the cadmium content in poisoned corpse was not evenly distributed, and the mass fraction of cadmium in kidney was 7 200.32 ng·g^-1, while that in brain was only 24.88 ng·g^-1. The recoveries of cadmium were in the range of 82.5%-94.1%, and RSDs (n=6) of the determined values for intra-day and inter-day were less than 10%.