基于滤光片提取光谱的流动注射-溶液阴极辉光放电检测研究

溶液阴极辉光放电-原子发射光谱法是近年来兴起的一种新型水体金属离子检测技术，它具有快速，在线和低成本检测的显著特点。以工业注射泵实现溶液阴极辉光放电激发源的流动注射进样，再以窄带滤光片分别提取Na，K，Ca，Li，Sr和Cs金属元素发射光谱信号，最后由光电倍增管和皮安表接收光谱信息光谱信号，实现了水质金属元素的检测。实验分析了注射容量分别为100和166 μL对1 mg·L-1的Na元素产生的信号强度的影响，研究发现其信号强度的相对标准偏差（RSD）分别为4.64%和1.95%，说明两种注射量稳定性都较好。为了获得更好的分析性能，实验分析了直流放电电压，狭缝的宽度以及光电倍增管供压等参数对信号强度的影响。实验结果表明，在直流放电电压为1 000 V，狭缝宽度为70 μm和光电倍增管供压为-800 V时获得了较高的信背比。采用此装置在流动注射模式下，测得了Na，K，Ca，Li，Sr和Cs六种金属元素检出限，分别为2.78，4.23，589，9.45，981和83.6 μg·L-1。实验最后对混合溶液标定物质中的Na和K元素进行了定量分析测量，测量的误差分别为7.5%和6.67%，精密度分别为1.24%和0.89%，研究结果表明基于滤光片提取光谱的流动注射分析-溶液阴极辉光放电-原子发射光谱方法具有较高的检测准确度。

Evaluation of Flow Injection-Solution Cathode Glow Discharge With an Interference Filter Wheel for Spectral Discrimination

Solution cathode glow discharge-atomic emission spectroscopy is a novel technology for metal ion detection in the aqueous solution that has emerged in recent years.It has the remarkable characteristics of rapid,real-time and low-cost detection.In this paper,an industrial injection pump was used to realize the flow injection analysis for the solution cathode glow discharge excitation source,and the narrow-band filter was used to extract the metal element spectral signals of Na,K,Ca,Li,Sr,and Cs,and the photomultiplier and ammeter were employed to obtain optical signals to electric signals,to realize the detection of metal elements in aqueous solution.The effects of injection volumes of 100 and 166μL on the signal intensity of 1 mg·L^-1 Na element was analyzed.The relative standard deviations(RSD)of the signal intensity are 4.64% and 1.95%,respectively,indicating that both injections had good repeatability.In order to obtain better analysis performance,the influence of parameters such as DC discharge voltage,slit width and photomultiplier tube supply voltage on signal strength were explored.The experimental results show that a high signal-to-back ratio is obtained when the DC discharge voltage is 1000 V,the slit width is 70μm,and the photomultiplier tube supply voltage is-800 V.the detection limits of six metal elements Na,K,Ca,Li,Sr and Cs were measured when the equipment works at flow injection mode,which was 2.78,4.23,589,9.45,981 and 83.6μg·L^-1.Na and K elements in the mixed solution were quantitatively analyzed and measured,the measurement errors were 7.5% and 6.67%,and the precisions were 1.24%and 0.89%,respectively,indicating that the homemade equipment can detect metal elements with high accuracy.