氢化物发生原子荧光光谱分析中的微秒脉冲供电空心阴极灯激发光源

Abstract

利用实验室研制的大电流微秒脉冲(HCMP)电源对AS,SE,Sb,Pb空心阴极灯(HCl)供电,研究了HCMP-HCl的发射光谱、电学性质、荧光光谱,评估其作为氢化物发生原子荧光光谱(Hg-AfS)激发光源的可行性。HCMP供电AS,SE,Sb,Pb HCl可在脉冲频率100~1 000Hz、脉冲宽度4.0~20μS、最大峰值电流4.0A下维持稳定放电;研究了HCMP-HCl特征谱线发射强度与脉冲电流、供电电压、脉冲频率、脉冲宽度等供电参数之间的关系;与目前商品常规脉冲供电(CP)的HCl相比,HCMP-HCl的供电脉冲宽度更窄、峰值电流更高。在优化的HCMP供电参数下,AS,SE,Sb HCl发射光谱中的原子线强度有较大幅度提高,可能用作Hg-AfS新型激发光源,而Pb HCl发射光谱中的离子线强度增强、原子线强度降低,不适合做Hg-AfS激发光源。以HCMP供电AS,SE,Sb HCl为激发光源的HCMP-HCl是一种极有发展前景的Hg-AfS新型激发光源。

The spectral,electrical and atomic fluorescence characteristics of As,Se,Sb and Pb hollow cathode lamps(HCLs)powered by a laboratory-built high current microsecond pulse(HCMP)power supply were studied,and the feasibility of using HCMP-HCLs as the excitation source of hydride generation atomic fluorescence spectrometry(HG-AFS)was evaluated.Under the HCMP power supply mode,the As,Se,Sb,Pb HCLs can maintain stable glow discharge at frequency of 100~1 000 Hz,pulse width of 4.0~20μs and pulse current up to 4.0A.Relationship between the intensity of characteristic emission lines and HCMP power supply parameters,such as pulse current,power supply voltage,pulse width and frequency,was studied in detail.Compared with the conventional pulsed(CP)HCLs used in commercial AFS instruments,HCMP-HCLs have a narrower pulse width and much stronger pulse current.Under the optimized HCMP power supply parameters,the intensity of atomic emission lines of As,Se,Sb HCLs had sharp enhancement and that indicated their capacity of being a novel HG-AFS excitation source.However,the attenuation of atomic lines and enhancement of ionic lines negated such feasibility of HCMP-Pb HCL.Then the HG-AFS analytical capability of using the HCMP-As/Se/Sb HCLs excitation source was established and results showed that the HCMP-HCL is a promising excitation source for HG-AFS.