Detection Of Metal Elements Of Skin In Electric Injury By Inductively Coupled Plasma Mass Spectrometry

Objective:To establish a method to detect metal elements of skin in electric injury using inductively coupled plasma mass spectrometry in animal experiments, and to explore the influence of formalin on this method, finally, put this method into the human skin in electric injury.Methods:Part 1: 24 New Zealand white rabbits were randomly divided into electric group of copper, electric group of iron, electric group of aluminum(n = 8). Animal experiment was established as following, one pole was fixed on the left hindlimb of the rabbit and the other on the left forelimb, and brass, copper, aluminum and iron electrode materials were used to make electrical marks on rabbit (220 V AC), then the injured skin and the same part skin of the right hindlimb were cut as samples, Finally, all the skins were detected by ICP-MS.Part 2: 32 New Zealand white rabbits were randomly divided into electric group of brass,electric group of iron (n = 16), and then each group were randomly divided into two subgroups (n=8), each subgroup was fixed 1 week or 6 months by formalin. The animal model was the same as part 1, and then brass and aluminum electrode material were used as electrodes to make electrical marks on rabbit (220 V AC), and the injured skin and the same part of the right hindlimb skin were sampled; then the injured skin was divided into two parts, one part was directly detected by ICP-MS, and another part was also detected by ICP-MS after fixed in formalin solution.Part 3: 8 cases of electrocution were collected, and the injured skin was cut along the edge, while the control sample was cut far away from the injured skin; Skin was divided into two pieces, and one piece was directly detected by ICP-MS, another piece was made into a histopathology.Results:Part 1: Comparing with control group, the levels of Cr, Ni, Cu, Zn and Pb showed higher in the group of brass shock(P<0.05); the levels of Cr, Cu and Pb were higher in group of the copper shock(P<0.05); the levels of Al, Cr, Mn, Co, Ni, Cu and Pb displayed stronger in group of aluminum shock(P<0.05); the levels of Cr, Mn, Fe and Ni showed higher in the group of iron shock(P<0.05). The types and levels of metal elements showed the significant difference between different electrode groups after electric injury.Part 2: Compared with the control group, the levels of Cr, Ni, Cu, Zn and Pb were higher in the group of brass shock(P<0.05),and these elements were still detected in the injured skin fixed for 1 week or 6 months by formalin, Furthermore, the concentration of Cr, Cu, Zn and Pb showed no significant difference between the instant injured group and the fixed group. Compared with the control group, the levels of Cr, Mn and Ni were higher in the group of iron shock (P<0.05),and the concentration of Fe, Cr and Ni showed no significant difference between the instant injured group and the fixed group.Part 3: Those cases have the clear spot and typical pathological diagnosis of electrical injury from No 1 to 4. In the case 1, the contents of Mn, Fe, Co, Ni, Cu, Zn and Pb were significantly increased; besides case 2, the levels of Mn, Fe, Cu and Pb were significantly increased; the concentrations of Mn, Fe, Ni and Pb increased Significantly in the case 3; In the forth case, the levels of Mn, Ni and Pb increased significantly.We couldn't make certain the process of the case 5 or 6, but we examined the suspicious electric mark by histopathology. Meanwhile, the contents of Mn, Fe, Ni, Cu, Zn and Pb increased significantly in case 5, the levels of Mn, Fe, Ni, Cu and Pb Increased significantly for the case of 6. In the case 7, Cr, Co, Ni, Cu, Zn and Pb were found in the suspicious electrode material from the scene, and the contents of Cr, Ni, Cu, Zn and Pb were significantly increased in the injured skin. In the case 8, Cr, Co, Ni, Cu and Pb were found in the electrode material from the scene, what's more, the levels of Co, Cu and Pb increased significantly in the injured skin.Conclusions:ICP-MS is an effective method to detect of the metal elements in electric injured skin , and which can provide more information to infer electric materials; Formalin have limited impact on detecting the metal elements in elelctric injuried skin using ICP-MS, after being fixed by Formalin.