液相阴极辉光放电原子发射光谱法高灵敏测定精铜矿中的铅和锌  

High Sensitive Determination of Pb and Zn in Refined Copper Ores Samples Using Liquid Cathode Glow Discharge-Atomic Emission Spectrometry

作　　者：俞洁[1] 朱淑雯 陆泉芳[1,2] 张志超 张晓敏 王星[1] 杨武[1] YU Jie;ZHU Shu-wen;LU Quan-fang;ZHANG Zhi-chao;ZHANG Xiao-min;WANG Xing;YANG Wu(Key Lab of Bioelectrochemistry and Environmental Analysis of Gansu Province,College of Chemistry and Chemical Engineering,Northwest Normal Univers ity,Lanzhou 730070,China;Editorial Department of the University Journal,Northwest Normal University ,Lanzhou 730070,China)

机构地区：[1]甘肃省生物电化学与环境分析重点实验室,西北师范大学化学化工学院,甘肃兰州730070 [2]西北师范大学学报编辑部,甘肃兰州730070

出　　处：《光谱学与光谱分析》2018年第11期3550-3557,共8页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21567025,21367023);甘肃省自然科学基金项目(17JR5RA077,17JR5RA075)资助

摘　　要：由于重金属毒性大,且在环境、动物和人体器官中易积聚,因而在矿石开采、冶炼和加工之前,监测其中的微量重金属显得尤为重要。著名的原子光谱仪器,如原子荧光光谱(AFS)、原子吸收光谱(AAS)、电感耦合等离子体(ICP)等已广泛用于各种样品中元素的检测,但它们体积大、能耗高、价格昂贵、气体消耗大,这些缺点严重阻碍了野外现场的连续监测。为了满足分析仪器的微型化趋势,1993年Cserfalvi开发了一种电解液阴极放电原子发射光谱(ELCAD-AES)技术并将其用于分析检测中。该装置中,待测溶液以8～10mL·min^(-1)的流速从细管顶端溢出,然后沿管壁流入装满电解液的35mL储液池中,以溢出溶液的液面作为放电阴极,在和流动液体电极相距2～4mm处放一金属W(Ti)棒为阳极,细管浸入电解液并尖端向上弯曲超出储液池液面1～3mm,细管顶端溢出的液体流入储液池并通过其中的碳棒与电源负极相连,从而构建放电系统。从那时起,为了提高激发效率和放电稳定性,人们对ELCAD进行了大量改进。基于ELCAD的特点,通过改进放电装置,建立了一种新的液相阴极辉光放电(LCGD)分析系统。该系统中,放电在直径0.5mm的铂针阳极和内径1mm的毛细管顶端溢出的溶液阴极之间的间隙中产生。毛细管上端和铂丝之间的间隙为2mm,毛细管插入石墨管且露出石墨管的距离为2.5mm。样品溶液以4.5mL·min^(-1)从毛细管顶端溢出流经石墨管上的凹槽,石墨管和电源负极连接。与ELCAD相比,LCGD的优点在于:Pt针做阳极,可形成尖端放电,从而降低能耗(<60W),提高激发效率;蠕动泵管上打结,可降低泵的脉动性,提高放电的稳定性;石墨管链接电源负极,删除ELCAD中的储液池,使样品消耗更少。为了评估方法的分析性能,用LCGD测定了HNO_3-HCl消化的精铜矿样品中的铅和锌。系统研究了放电稳定性以及放电电压、溶液流速、支持电�Monitoring of trace heavy metal ions in ores samples before the mining,smeltin gand processing is of great importance due to it high toxicity and gradual accumul ation in the environment as well as in animal or human organs.The well-known atomic spectrometry analytical instruments,such as atomic fluorescence spectro metry(AFS),atomic absorption spectrometry(AAS)and inductively coupled plasm a-atomic emission spectrometry(ICP-AES),have been extensively employed for the determination of metal elements in various complex samples.However,these analytical instruments require bulky and costly devices,high power and large gases consumption.These shortcomings restrict their use within labora tory,preventing their use for field measurement and continuous monitoring.To meet the trend of miniaturization in analytical instrumentation and the requi rements of on-line detection in field,electrolyte cathode discharge(ELCAD)h as been developed by Cserfalvi in 1993 as an important tool in atomic spectrum a nalysis for element determination of liquid samples.In the original apparatus of ELCAD,the sample solution is acted as cathode,which overflows with typi cal flow rate of 8~10 mL·min-1 from a pipette into about 35 mL reservoir completely filled with electrolyte solution,and a counter-electrode(mostly W or Ti rod)above it(2~4 mm)is the anode.The pipette is immersed into electrolyte solution and then curved upwards about 1~3 mm from the reservoir containing a grounded graphite electrode to make it electrically conductive.Since th en,in order to improve the emission efficiency and discharge stability,many improvements for excitation source of ELCAD have been developed.In the present work,a novel liquid cathode glow discharge(LCGD)was successfully constructed based on the principle of ELCAD,in which the glow discharge plasma was genera ted between the needle-like Pt anode(diameter 0.5 mm)and electrolyte(served as the liquid cathode)overflowing from a quartz capillary(1.0 mminner diameter).The vertical gap betwee

关 键 词：液相阴极辉光放电 原子发射光谱 精铜矿 微量重金属 高灵敏测定 

分 类 号：O657.3[理学—分析化学]