Determination Of Trace Toxic Elements In Dinosaur Skeleton Fossils By Atomic Spectrometry

Hydride generation atomic fluorescence spectrometry was for the first time utilized to determine trace toxic elements, arsenic, antimony, bismuth, mercury, selenium, tellurium and lead, in the skeleton fossil of a dinosaur and its adjoining rock unearthed in Sichuan Province. The instrumental limits of detection (LODs) for these elements were 0.03, 0.2, 0.3, 0.009, 0.2, 0.2, and 0.6 g/L, respectively. The LODs for these elements except lead were compared favorably to those by ICP-AES and ETAAS, and the LOD for mercury approached that by ICP-MS. The analytical results showed that the content of antimony, bismuth, mercury, selenium, and tellurium in the skeleton fossil were in good agreement with those in its adjoining rock with different digestion procedures. The arsenic concentration was abnormally high in the skeleton fossil. The lead level in the skeleton fossil was lower than that in its adjoining rock. The accuracy of the proposed method was confirmed by use of two geological reference samples, GBW07310 and GBW07108, of similar matrices. The recoveries of standard addition for arsenic were found to be from 97% to 109%. Arsenic in the dinosaur skeleton fossils from Anyue, Kaijiang, Guangyuan, Jianyang were also determined by ICP-AES, for the comparison with the analytical results obtained by HG-AFS. The samples were digested with aqua regia in boiling water bath, avoiding the use of hydrofluoric acid. The analytical results were consistent with those by HG-AFS. With (NH4)2HPO4 as a chemical modifier, trace lead in a dinosaur skeleton fossil and its adjoining rock was determined by ETAAS. The preliminary analytical results showed that the lead level in the fossil was generally equivalent to that by HG-AFS. The tiny difference for lead in the skeleton fossil and its adjoining rock may be due to the sample heterogeneity. The recovery of the method was in the range of 96% to 113%, and the relative standard deviation of the method was less than 9.5%. It is proved that HG-AFS is a simple, reliable, sensitive yet relatively inexpensive analytical method, compared to ICP-AES, ICP-MS and ETAAS. The interesting analytical results showed that the arsenic concentration was abnormally high in the skeleton fossil, compared to that in the adjoining rock. The established analytical method and the results may be helpful in revealing the mystery of the mass extinction of the dinosaur fauna. The analytical results, together with other data available to date, supported the argument that the arsenic toxicosis could be a contributing factor for the mass extinction of the dinosaur fauna in Sichuan Province of China.