开缝石英管原子化技术的改进

An Improvement of Slotted Quartz Tube Flame Atomiation Technique

近年来,为提高火焰原子吸收光谱法的灵敏度,先后研究过水冷石英管和开缝石英管(简称缝管)原子化技术.前者使灵敏度提高1～2个数量级,后者只提高几倍.缝管技术比水冷石英管技术的装置简单,操作方便快速,但因其灵敏度不高,应用受到限制.本文以镉为例,探讨了提高缝管技术灵敏度的途径.

The slotted quartz tube atom-trapping technique with a high sensitivity is reported in the paper.The effects of various conditions (flame status,air flow,collection time,medium of solution and slotted tube height etc.) on the sensitivity of cadmium was investigated in detail.The results shew that the best sensitivity is obtained when fuel-lean and fuel-rich flames are respectively used for collection and release.The characteristic concentration of 3.7×10-5μg/mL was obtained for 0.4 ng/mL of cadmium solution being trapped for 1 min.The sensitivity of cadmium may be increased 270-fold in comparison with the convention flame atomic absorption spectrometry.The coefficient of variation is 4.1 % for 0.4 ng/mL cadmium solution after trapping for 1 min (n=11).The cadmium in taxodium ascenders has been determined directly.