| By using Atomic Absorption method Cu, Fe, Zn, Ca, Pb, Cd in human hair were determined. The digestion method, apparatus, conditions and other factors were studied to find the best conditions for the determination. On this basis, the hair of autistic children, the hair of their parents and the hair of healthy children were collected to study. The results were compared and analyzed to find the regularity.The results show that Cu, Fe, Zn, Ca in human hair were determined by wet digestion and flame atomic absorption spectrometry method. 1.0g sample to 15mL nitric acid used as a digestive,2 hours digestion time. The best instrumental condition was determined by orthogonal experiment. Pb, Cd in human hair were determined by microwave digestion and graphite furnace atomic absorption spectrometry with (NH4)SO4+KH2PO4 as a matrix modifier. The best experimental conditions were like that:digestive HNO3-H2O2 (4:1,V:V), microwave digestion pressure 1.0Mpa. Drying temperature of Pb, Cd were 100℃, Pb ash temperature 500℃, atomization temperature 1700℃, Cd ashing temperature 600℃, atomization temperature 1900℃. The precision and recovery meet the experiment requirement.Hair samples of autistic children, their parents and the healthy children were collected to determine the contents of Cu, Fe, Zn, Ca, Pb, Cd. The results were compared among the three groups to give the association between trace elements and autism.The determination results show that there is a lack of certain trace elements in the autistic children's hair, such as Ca, Zn. Comparing between autistic and healthy children, there is no evidence to prove that harmful elements such as Pb, Cd have an association with autism, for the contents of Pb, Cd in the autistic children's hair are not high. Through the comparison between children and their parents of measured data, it shows that the Ca, Zn contents of children's hair are lower, and Cu, Fe, Pb, Cd contents are irrelevant between children and their parents. |
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