Study On The Determination Of Lead By Thermospray Flame-heated Quartz Furnace Atomic Absorption Spectrometry

Flame atomic absorption spectrometry (FAAS) is one of the most frequently used techniques in trace element determination with the advantages of simplicity, fast, good reproducibility and wide linear range. However, its coverage cannot be extended to ultra-trace analysis because of its relative low sensitivity. The reasons lie in the poor performance of pneumatic nebulization (2%-5%) and the short residence time of free atoms in absorption volume (3-5 ms). In order to improve the sensitivity of conventional FAAS, many sensitivity-enriching methods have been proposed, such as atom trapping technique, boat-in-flame technique and Devels cup technique. In 2000, a new flame method, named flame furnace technique, was proposed by Berndt, with sample introduction by using HPLC pump aided-beam injection or thermospray. In this new approach, due to the total sample introduction and significant enlarged residence time of free atoms in optical path, the delectability of conventional FAAS was greatly improved.In the current work, we studied the feasibility of using quartz tube as flame furnace for the determination of lead. A systematic investigation and optimization was carried out, including the size of the tube, tube with or without additional holes at the bottom and the material of thermospray capillary (quartz and stainless steel), to achieve optimal performance of the proposed method. Detection limit of 1μg/L was obtained when using stainless steel capillary and quartz tube with additional holes, which was the best performance in the investigated series (thermospray...