الفهرس 
cover EnglishOnly 14 pages are availabe for public view
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Abstract
Analysis of trace elements in mammalian hair has the potential to reveal retrospective information about an individual’s nutritional status and exposure to pollutants. As trace elements are incorporated into the hair during hair formation, segments of hair may reflect the body burden of most elemental components. Mammalian hair differs greatly among organisms in cross sectional diameter as well as elastic and tensile behavior. So the present work was conducted on horse hair as a preliminary step towards determination of the optimum conditions for evaluation of elemental content of human hair using LIBS technique. Using LIBS technique, qualitative analysis of atomic and ionic species of elemental content was performed. Also results of quantitative analysis obtained through LIBS technique on hair samples were compared with the traditional AAS technique on digested acidified solution of the same samples. The effects of the experimental parameters on the emission lines were studied and the local thermodynamic equilibrium in produced plasma was verified. The obtained results for horse hair samples indicated that the optimum measurement conditions were obtained at gate time delays between 1000-2000nsec, laser pulse energy of 100mJ with fixed gate width of 5000nsec and 50 successive shots. Similarly, the optimum measurement conditions for human hair samples were obtained at gate time delay of 1500nsec, laser pulse energy of 100mJ with fixed gate width of 5000nsec and 50 successive shots. For quantitative analysis, carbon as an internal standard matrix element was considered as reference element in an attempt to improve the precision repeatability of the measurements. The relative mass concentration for selected elements was calculated as the ratio number of atoms and ions of element to reference element. The data obtained using both LIBS and AAS techniques showed non-significant difference (statistical t-test at p<0.05) indicating the precise performance of LIBS technique (at the proposed optimum conditions) as a promising tool, non-invasive and easy trend for characterization and identification of heavy metals in biological materials.