| Although the technique of chemical vapor generation has been developed forover l00 years, it sill plays an important role in modern analytical atomicspectrometry until today The technique has become popular fOr thedetermination of trace elements in the complex matrices and new aPproachescontinuously comes forth to improve the sensitivity and expand the scope ofaPplications. This work concerns with the deve1opment of new chemical vaporgeneration techniques and their aPplication in the analysis of trace elements inChinese medicinal materials.This thesis comprises six parts: l) a review of the chemica1 vaPor generationtechniquesthe history current statlls and future prosPects; 2) a novel sampleintToduction technique for the simultaneous determination of As, Se, Ge and Hgin Chinese medicinal material; 3) cold vaPor generation techniques for thedetermination of selected noble metals using MRBHG couPled with ICPfMS; 4)pyrolysis coupled with atomic absorption spectrometry for the determination ofmercury in Chinese medicinal materials, 5) aPplication to real Chinesemedicinal samples f pyrolysis coupled with AAS fOr the determination of Hg,ICP/MS for As, Cd and Pb -- interlaboratory data comparisons, and 6)recommended future work: temperature program pmplysis for mercuryspeciation in solid samples of Chinese medicinal materials; and the mechanisticstudy on chemical vapor generation using MRBHG coupled with AAS.ln the first chapter of the thesis, more than 100 references were reviewed whichgives a detaiIed introduction to the history of the chemical vapor generationtechniques. The vapor forms were classified according to the methods of- 4 -klIkiff/ffiiffop\ty4t2 ijl A$JiA&RAYfop%6}tIsth roI{yffigeneration. The modem hyPhenated techniques of chemical vapor generationcoupled with other techniques were introduced and the advantages andshortcomings of this technique were evaluated.In chaPter 2, a novel technique of Moveable Reduction Bed Hydride Generator(MRBHG) was aPplied to the hydride generation or cold vaPor generation of As,Se, Ge, and Hg species in Traditional Chinese Medicinal Material (TCM). Thesimultaneous determination of multi-elements was perfonned with ICP-MS. Asolid reduction system involving the use of potassium tetraborohydride andtariaric acid was performed to generate metal hydride or cold vapor efficientlyThe factors affecting the metal cold vaPor generation were studied. The mainadvantage of the technique is that only 4UL saxnple volume was required for thecold vaPor generation. The absolute detection limits of all elements studied arein the pg level.In the third chaPtef, some noble metals such as gold, silvef, platinum andpalladium were fOund to be able to generate volatile sPecies by a noveltechnique of Moveable Reduction Bed Hydride Generator (MRBHG) couPledwith ICP-MS. A solid reduction system involves the use of potassiumtetTahydroborate and tartaric acid was employed to generate metal hydrides orcold vaPor for sample introduction into ICP/MS. The factors affecting theefficiency of metal cold vaPor generation were evaluated and operationconditions were optimized. The main advantages of the technique are that only4pL sample volume was required for cold vapor generation, and no gas-liquidseparator was needed. The absolute detection limits of all elements studied arein the pg range. Interference of 25 kinds of foreign ions on the analysis of thesenoble metals has been investigated. The method has been proven to be suitablefOr the analysis of noble metals in samples with complex lnatrices.- 5 -Chapter 4 described the coupling of a pyrolysis unit to an atomic absorptionspectrometry for the analysis of mercury in solid samples of Chinese MedicinalMaterials (CMMs). This highly sensitive analytical technique provides a simpleand raPid method for the screening of Hg in CMM samples including raw herbs,mineral drugs and their derived formulate...
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