Inductively Coupled Plasma Mass Spectrometry(icp-ms) And Laser Ablation Techniques And Their Application In Solid Materials

Element analysis of solid materials has an important status and role in the field of metallurgy, geology, environment , bionomy, semiconductor, nuclear and radioactive waste materials. Inductively coupled plasma mass spectrometry(ICP-MS) and laser ablation ICP-MS(LA-ICP-MS) are being increasingly used for the characterization of solid materials. In order to deal with refractories or avoid the serious drawback of time-consuming, cumbersomeness and the risk of contamination when sampling, appropriate digestion strategies or direct solid sampling techniques are coupled with ICP-MS. A method has been established for the determination of B, Ti, Zr, Nb, Sn, Sb, Ta, W and Pb in low alloy steels by high pressure digestion-ICP-MS. Some elements in materials were refractory or hydrolysable during sampling, or with extremely low concentration, which could be solved by adopting the optimized condition of digestion. The method developed was validated using several low alloy steel standard reference materials. Based on the study of solution nebulizer(SN)-ICP-MS, LA-ICP-MS was applied for the determination of harmful and hazardous elements, Pb, Cd, Cr, Hg in plastic materials. Several polypropylene reference materials including a blank disk have been used as standards for calibration, and different practical samples have been analysed. With little sample preparation steps, precise and accurate analysis, this method could meet the need of practical detection.This dissertation consists of four chapters. In the first chapter, the significance and conventional methods of element detection about solid materials are described. Principles and state-of-the-art of ICP-MS and LA-ICP-MS are also investigated. The purpose, meaning and major content of this thesis are presented in this chapter.In Chapter Two, the significance of the nine elements analysis in low alloy steels are described, compactly, and a method is developed for the determination of B, Ti, Zr, Nb, Sn, Sb, Ta, W and Pb in low alloy steels by high pressure digestion-ICP-MS. The effect caused by different mixed acids, temperature and time of digestion was studied, especially. The HF tolerance nebulizer system was used for the solution introduction. After optimizing the operation parameters, the interferences caused by polyatomic ions were investigated, as well as the signal shift and matrix effect. At the end, the analytic result of sample using this method are discussed. The third chapter is about the application of LA-ICP-MS in analysis of harmful and hazardous elements, Pb, Cd, Cr, Hg in plastic materials. Firstly, the routine analytical techniques and the potential capability of LA-ICP-MS for plastic are introduced. The ablation behavior about single point and single line scan mode are studied. Instrumental operation condition, including laser energy, pulse length, ablation size, scan rate, defocus distance, RF power, sample depth and carrier gas rate are optimized according to the sensitivity and stability. Fractionation index was calculated in order to estimate the fractionation effect, which was little for the interesting elements except Hg. The determination of Hg suffered from serious memory effect which was put down to the adsorption by sample surface. Several polypropylene reference materials including a blank disk have been used as standards for calibration, and different practical samples(PVC, ABS, PPS, PTFE), as well as two reference materials(PVC, PE), have been analyzed, showed good agreement with ICP-AES values. The detection limit of Pb, Cd, Cr and Hg was 0.002, 0.001, 0.08 and 1.5 mg/kg, respectively.Conclusion and problems existed in the techniques of ICP-MS and LA-ICP-MS are subjected in the last Chapter, and prospects are advised in succession.