液体阴极辉光光谱仪应用于阴阳离子检测的研究

发布时间：2018-02-11 19:46

本文关键词： 辉光放电离子色谱阴离子吸附铅离子　出处：《东华大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着现代工业的发展,环境污染问题日益严重,大量的重金属及有毒阴离子被排入土壤、河流及海洋等水体中,严重危害土壤及水体生态环境。因此,实现便捷、高效、快速的金属离子及阴离子检测技术对于环境监测具有重要意义。目前,液体阴极辉光放电原子发射光谱法(Solution Cathode Glow Discharge Atomic Emission Spectroscopy,SCGD-AES)是其中发展最快,最有应用潜力的金属离子检测方法之一,在原子光谱分析中作为一种新兴的元素检测技术而备受关注。与传统原子光谱仪器(原子吸收光谱、等离子体光谱/质谱等)相比,液体阴极辉光放电具有可在大气压下操作,不需乙炔或高纯氩气等工作气体,仪器功率要求低(放电功率小于100 W),样品进样时无需使用雾化器等优点。然而低温等离子体由于其激发温度的限制,对某些重金属离子的检测灵敏度还无法满足应用需求。本文的研究内容主要围绕实验室已构建的液体阴极辉光放电光谱装置而展开。首先,对仪器的原子化器进行了改进,使得等离子体放电的稳定性提高,为以后仪器的小型化及便携式提供了可能。实验考察了电压大小、进样流速、电解液种类、电解液pH值对仪器性能的影响。结果表明,仪器操作的最佳条件为:放电电压为1060 V,进样流速为2 mL/min,p H=1的硝酸作为电解液溶液。为了提高仪器对重金属铅的灵敏度,采用固相萃取技术将液体阴极辉光放原子发射光谱仪与流动注射仪联用,并根据文献制备了一种氧化石墨烯/介孔SBA-15复合材料作为铅的吸附剂,建立了在线分析检测溶液中铅的分析方法。实验确定了联用装置的最佳条件,固相萃取盘填料量为30 mg,富集流速为1 mL/min,洗脱剂为0.1 M硝酸,对铅的富集倍数为15。为了验证方法的可靠性,对标准物质GBW09101b(人发)及GBW07310(水系沉积物)进行分析,实验结果与电感耦合等离子体质谱(Inductively Coupled Plasma-Mass Spectrometry,ICP-MS)测定值比较相一致,并与参考值吻合。在Schwartz等人的基础上,采用锂离子交换柱作为交换器,将不同阴离子所配位的H+等摩尔比地置换成锂离子,并利用液体阴极辉光光谱仪作为离子色谱的检测器,通过检测锂离子的变化值实现对阴离子的检测,建立了一种可用于阴离子分析的高灵敏检测方法。联用装置检测阴离子的最佳条件为:最佳电压为1060V,最佳补充液流速为0.9 mL/min,最佳淋洗液浓度为15 mM的KOH。在该优化条件下,对F~-、Cl~-、Br~-、NO_2~-、NO_3~-、CH_3COO~-和SO_4~(2-)等阴离子的检出限在4~17μg/L之间。将此方法用于自来水及河水中阴离子的检测并与离子色谱仪的检测值比较,结果令人满意。
[Abstract]:With the development of modern industry, the problem of environmental pollution is becoming more and more serious. A large number of heavy metals and toxic anions are discharged into soil, rivers and oceans, which seriously endanger the ecological environment of soil and water bodies. Rapid detection of metal ions and anions is of great significance for environmental monitoring. At present, the solution Cathode Glow Discharge Atomic Emission spectroscopySCGD-AESs are the fastest growing. One of the most promising methods for the detection of metal ions has attracted much attention as a new technique for the detection of elements in atomic spectrum analysis, compared with conventional atomic spectrometer (atomic absorption spectrum, plasma / mass spectrometry, etc.). Liquid cathode glow discharge can be operated at atmospheric pressure, without the need of acetylene or high purity argon and other working gases, The instrument requires low power (discharge power less than 100WN, sample injection without atomizer, etc.). However, the low temperature plasma is limited by its excitation temperature. The detection sensitivity of some heavy metal ions can not meet the requirement of application. This paper mainly focuses on the liquid cathode glow discharge spectrometer which has been constructed in the laboratory. Firstly, the atomizer of the instrument is improved. The stability of plasma discharge is improved, which provides the possibility for the miniaturization and portable of the instrument in the future. The effects of voltage, injection velocity, electrolyte type, pH value of electrolyte on the performance of the instrument are investigated experimentally. The optimum operating conditions are as follows: the discharge voltage is 1060V, and the injection rate is 2 mL / min / min / h ~ (-1) nitric acid as electrolyte solution. In order to improve the sensitivity of the instrument to heavy metal lead, Solid phase extraction (SPE) technique was used to combine liquid cathodic glow discharge atomic emission spectrometer with flow injector, and a graphene oxide / mesoporous SBA-15 composite was prepared as the adsorbent of lead according to the literature. An on-line analytical method for the determination of lead in solution was established. The optimum conditions of the combined device were determined. The solid phase extraction disk packing amount was 30 mg, the enrichment flow rate was 1 mL / min, and the eluent was 0.1 M nitric acid. The enrichment ratio of lead is 15. In order to verify the reliability of the method, the standard materials GBW09101b (human hair) and GBW07310( sediment of water system) are analyzed. The experimental results are in good agreement with the results of inductively Coupled Plasma-Mass spectrometric ICP-MSs determined by inductively coupled plasma mass spectrometry (ICP-MS). On the basis of Schwartz et al, the lithium ion exchange column was used as the exchanger, the H coordinated by different anions was replaced to lithium ion at the same molar ratio, and the liquid cathodic glow spectrometer was used as the detector of ion chromatography. The detection of anions can be achieved by detecting the variation of lithium ions. A highly sensitive detection method for anion analysis was established. The optimum conditions for the detection of anions by the combined device were as follows: the optimum voltage was 1060V, the optimal flow rate of the supplementary solution was 0.9 mL / min, and the optimum concentration of eluant was 15 mm. The detection limits of the anions such as FCU ClCl-CU Br-nO _ 2C _ 2C _ 2C _ 2C _ (C) -C _ 3COOO ~ (-) and so _ (4) C _ (2)) are in the range of 4 ~ 17 渭 g / L. The method has been applied to the determination of anions in tap water and river water with satisfactory results compared with the determination values of ion chromatograph. The results are as follows: (1) the detection of anions in tap water and river water is satisfactory.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.3

【参考文献】