氢化物发生-原子吸收光谱法测定食品中的汞

研究了采用氢化物发生-原子吸收光谱法测定食品中痕量汞的方法,通过采用氢化物发生器,选择合适浓度的载流和硼氢化钾,获得了较为满意的分析结果。在测定汞含量5～20μg/kg的食品标准样品时,测试结果相对标准偏差RSD为2.2%～3.7%,回收率为84.9%～97.5%,检出限为0.2μg/L,完全满足食品行业汞元素痕量检测要求,操作简便、快速。     

自制T型石英管氢化物原子吸收法测定水中汞

汞是环境中重要的有毒元素。简单、快速、准确地测定其含量,对保障人类免受其毒害有重要作用。目前,测定汞主要用测汞仪,有些产品性能很不稳定,原子吸收测汞也有探讨。本文用自制T形石英管测定水中汞,结果表明,该法样品用量少、灵敏、精密度高,检出限低,有结构简单、成本低、使用方便等优点。 1 试验部分 1.1 主要仪器与试剂 WFX-1F型原子吸收分光光度计(北京第二光学仪器厂) HG-25型氢化物发生器(北京高智技术研究所) 仪器工作条件:波长-253.7nm,光谱通带宽度-0.2nm,原子化温度-室温,载气流量-200ml·min~(-1)。 纯水:电导率0.5μs·cm~(-1)(北京化工厂) 汞标准液及应用液:氯化汞(GR)配制 其余试剂均为AR级 载气:高纯氩 T型石英管规格(见图)     

氢化物发生-原子吸收光谱法测定环境水样中的汞

报道了氢化物发生-原子吸收光谱法测定环境水样中汞的方法。方法操作简便、线性好、灵敏度高(特征浓度为0．25mg／L／1％),精密度和准确度好,直接测定信号值,提高了分析速度,各项技术指标均能满足环境监测规范要求。     

氢化物原子吸收分光光度法测定食品中砷

食品样中砷的测定一般用银盐法,然而此法灵敏低操作繁琐,本法用氢化物原子吸收分光光度法测定食品中的砷则操作简便、快速、灵敏度高.方法灵敏度为0.8ng·ml~(-1),检出限为0.5ng·ml~(-1).1 试验部分1.1 仪器与试剂WYX-402型原子吸收分光光度计HCF氢化物发生器T型石英管砷标准溶液:100ng·ml~(-1)混合酸:硝酸+高氯酸(4+1)盐酸溶液:0.5mol·L~(-1)硼氢化钾:5g·L~(-1)还原剂:称取碘化钾15g、抗坏血酸10g溶解于离子水,定容至100ml.     

氢化物发生原子吸收法测定卡托普利

根据卡托普利与醋酸铅反应定量生成沉淀的特点 ,通过用氢化物发生原子吸收法测定沉淀中的铅 ,可间接测定卡托普利的含量。平均回收率 99.8% ,RSD值为 1 .6%     

顺序注射-氢化物发生原子吸收法测定砷

通过在气液分离器的液体出口处增置微型电磁阀,延长样品和还原剂NaBH4在气液分离器中的反应时间,实现了单注射泵顺序注射-氢化物发生原子吸收法测定砷。本法自动化程度高,分析速度112次／h,样品消耗量为0．4mL;4μg/L As测定10次的相对标准偏差为2．0％;检出限0．09μg/L。用于标样中砷的测定,结果满意。     

浊点萃取-氢化物发生原子吸收光谱法测痕量汞

提出了浊点萃取预富集氢化物发生-原子吸收光谱法测定痕量汞的新方法。详细探讨了溶液pH值、表面活性剂浓度、平衡时间等因素对浊点萃取效果的影响。在优化的实验条件下,该法对汞的富集倍数为20倍,检出限为0.039μg/L,相对标准偏差(RSD)为4.8%(n=11)。所建立的方法用于天然水中痕量汞的测定,分析结果满意。     

流通式电化学氢化物发生法原子吸收测定硒的研究

采用自行研制的以铅作阴极、石墨作阳极无隔膜分隔的流通式电化学氢化物发生器,电解产生的气体经气液分离器后直接送入火焰原子吸收进行测定,因无外加载气减少了稀释提高了灵敏度。研究了各种影响因素,选择了最佳条件,以0．5mol／L硫酸作电解液,以1．3mL／min流速通过氢化物发生器,电解电流为2．0A。结果表明硒质量浓度在0～5μg／mL范围内呈良好的线性关系,其相关系数为0．9988,相对标准偏差为4．4％,特征质量浓度为0．0397μg／mL,检出限为0．084μg／mL。     

Determination of zinc in food using atomic fluorescence spectrometry by hydride generation from organized media

A method was proposed for the determination of zinc by atomic fluorescence spectrometry with hydride generation from surfactant-based organized media. The ability of different nature micelles to improve hydride generation of zinc was investigated using an intermittent flow hydride generator and the possible mechanism was discussed. The advantages of hydride generation from the organized media of cetyltrimethylammonium bromide (CTAB) were contrasted with that from aqueous media in sensitivity and precision of the zinc determination. The micellar media of CTAB improved the hydride generation processes of zinc both thermodynamically and kinetically. In addition some transition metals, presumably metal borides, were found to catalyze the hydrogenation of zinc. The proposed method has been validated by the determination of zinc in the certified reference materials using the standard addition method with satisfactory result.     

Determination of the different oxidation states of As and Sb by a new electrochemical hydride generator coupled with atomic fluorescence spectrometry

A novel disk electrochemical hydride generator has been developed for the determination of As and Sb. Compared with the traditional thin-layer cell, the disk cell combined the advantages of quick assembly and easy operation. This electrochemical system for hydride generation in neutral buffer solutions has been studied for analytical usefulness in coupling with atomic fluorescence spectrometry. It was found that the use of neutral phosphate buffer solution could markedly increase the fluorescence intensity of As(III) and Sb(III) and reduce the impact of cathode erosion on the stability of signal intensity. At the same time, the fluorescence intensity of As(V) and Sb(V) were almost suppressed totally. The detection limits (3σ) of 0.031 μg L⁻¹ As(III) and 0.026 μg L⁻¹ Sb(III) in aqueous solutions were obtained, respectively. The precisions (n = 11) for 20 μg L⁻¹ As(III) and Sb(III) were 2.0% and 2.7%, respectively. The method was successfully applied for determination of different oxidation states of As and Sb in environmental samples.     

树脂分离-氢化物发生-原子荧光光谱法测定食品中无机砷、一甲基胂和二甲基胂

建立了用阴离子交换树脂分离-氢化物发生原子荧光光谱法测定食品中无机砷、一甲基胂和二甲基胂的方法.分别从样品上样条件及二甲基胂、一甲基胂、 As(Ⅲ)和As(Ⅴ)分离条件进行了优化.研究了树脂处理程序对分离的影响,并探讨了共存离子对测定砷的干扰和消除的方法.对方法的适用范围做了研究.本方法具有操作简便、快速、灵敏度高等优点.检出限(以砷计)分别为: 无机砷0.34 μg/L,一甲基胂0.57 μg/L,二甲基胂0.46 μg/L.     

Determination of selenium in vegetables by hydride generation atomic fluorescence spectrometry

A digestion mixture of H₂SO₄/HNO₃/H₂O₂/HF/V₂O₅ was investigated for decomposition of plant samples and sensitive detection of selenium was achieved by hydride generation atomic fluorescence spectrometry (HG-AFS). The method was found to be accurate and reproducible, with a low detection limit (DL) (0.14 ng g⁻¹ solution). The repeatability of the determination was mostly around 10%, the reproducibility over a period of 8 months for determination of selenium in the standard reference material Trace Elements in Spinach Leaves, NIST 1570a, was 9% and the relative measurement uncertainty was 7% using a coverage factor of 2.3 at 95% probability. The average recovery of the whole procedure was 90%. The characteristics of this method are simple and inexpensive equipment, low consumption of chemicals and the ability to analyse many samples in a short time. The whole procedure was carried out in the same PTFE tube, and in addition only a simple cleaning procedure is needed. As a consequence of all these advantages, the described method is suitable for environmental and nutritional studies. The selenium content was determined in 44 vegetable samples from different regions of Slovenia and the contents found were in the range 0.3-77 ng g⁻¹ wet weight.     

Determination of arsenic in sea water by sorbent extraction with hydride generation atomic absorption spectrometry

A rapid and sensitive sorbent extraction hydride generation-flow injection analysis atomic absorption spectrometric (HG-FIAS-AAS) method is described for the determination of As(III) and As(V) based upon online preconcentration on a microcolumn packed with activated alumina. In the present procedure these arsenicals are complexed with quinolin-8-ol-5-sulphonic acid from neutral solutions in the flow injection system and adsorbed on the column. The preconcentrated species are eluted with 10% HCl, mixed with 0.5% sodium borohydride and carried to the HG-FIAS cell with a carrier gas flow rate of 75 ml min(-1). The retention efficiency is found to be better than 98% with sensitivity enhancement of 12 and 10 for As(III) and As(V), respectively, for a 20 s preconcentration period. The respective detection limits are 0.05 and 2 ng ml(-1) for As(III) and As(V). The throughput of the samples is found to be 60 h(-1), with a loading time of 20 s. The method has been applied to sea water samples.     

氢化物发生原子荧光光谱法测定磷酸中的砷

采用HCl处理H3PO4试样，氢化物发生原于荧光光谱法测定As，对仪器条件、HCl酸度、预还原剂用量、还原剂用量、共存干扰进行了试验，方法的检出限为0．18ng／mL，测定精密度1．9％-3．0％，回收率为96．0％-98．0％。     

开叉毛细管HG-FAAS测定地质样品中的锑、铋

氢化物发生原子吸收法(HG-FAAS)广泛应用于冶金、地质、环境、医药和食品分析等领域中。研究表明,氢化物发生法的检出限、测定精度以及干扰等情况与原子化器和氢化物发生器的结构以及传输过程有关[1]。郭小伟等[2-4]研制了用于火焰原子吸收光谱分析的双毛细管喷雾器,并利用其测     

Determination of lead in wines by hydride generation atomic absorption spectrometry.

The optimization of lead hydride generation in aqueous ethanolic media and the influence on its generation of the wine components, both white and red, have been studied. These interferences were overcome by careful control of the parameters affecting hydride generation and the procedure was applied to the determination of Pb in wines. The method is fast, accurate and sensitive and can be used to quantify 24 ppb of Pb in wines.     

Determination of total arsenic in seawater by hydride generation atomic fluorescence spectrometry

In this work, the determination of total As in seawater by hydride generation atomic fluorescence spectrometry was studied. The influence of the chemical, flow and instrumental parameters were investigated and optimized. The pre-reduction of As(V) to As(III) was performed using KI plus ascorbic acid in 3.5 mol L^− 1 HCl medium. No multiplicative interference was present and external aqueous calibration could be used. The limit of detection was 36 ng L^− 1, while the repeatability was 2% (n = 10), at a 500 ng L^− 1 concentration level. The sample throughput was 15 h^− 1 if triplicate measurements were made. The accuracy was assessed by the analysis of a seawater certified reference material and excellent agreement between the obtained and certified values was verified. The procedure was used for the analysis of seawater offshore samples collected at the Brazilian coast and results ranging from 860 to 1200 ng L^− 1 were found.