氢化物发生-原子荧光光谱法间接测定痕量碘的研究

提出了氢化物发生-原子荧光光谱法间接测定痕量碘的新方法,在弱酸性介质中,以Ⅰ--[Cd(Phen)3]2 -硝基苯为萃取体系,经0.24 mol/L的HCl反萃取后,用原子荧光光谱法测定镉量,从而间接测定碘.方法的线性范围为0～20 μg/L;相对标准偏差为8.5%;检出限为0.8 μg/L;回收率为74.63%～90.80%.方法已用于测定自来水中的碘量.     

高效离子色谱法测定水杨酸

报道了用抑制型高效离子色谱法测定水杨酸的方法。本法测定水杨酸的线性范围为1.2~360 mg/L,线性方程的相关系数为0.9997,检出限为0.5 mg/L。对120mg/L的水杨酸溶液10次平行测定的相对标准偏差为2.01%。加标回收率在95.7%~100.3%之间。该法已应用于测定脚癣药水中水杨酸的含量,获得满意结果。     

气相分子吸收光谱法快速测定土壤中亚硝酸盐氮

建立气相分子吸收光谱法快速测定土壤中亚硝酸盐氮的方法。土壤样品采样用200 mL 1 mol/L的氯化钾溶液浸提,于20℃恒温条件下震荡60 min,静置离心。在0.5 mol/L柠檬酸+30%乙醇介质中,用气相分子吸收光谱法测定亚硝酸盐氮含量。结果显示,在0～2.0 mg/L范围内亚硝酸盐氮质量浓度与吸光度呈良好的线性关系,线性相关系数为0.999 9,方法检出限为0.010 mg/L,相对标准偏差为1.32%(n=6),样品加标回收率为93.0%～97.0%。该方法具有操作简单、分析快速准确、干扰少等优点,适用于土壤中亚硝酸盐氮的测定。     

酶荧光毛细管分析法测定微量血清中乳酸脱氢酶活性

基于丙酮酸/还原型辅酶I/乳酸脱氢酶(LDH)/乳酸/氧化型辅酶I荧光猝灭体系和荧光毛细管分析技术,建立了可用于微量样品中LDH酶活性测定的方法。优化的测定条件为:激发及发射波长分别为350和460nm;测定温度为25℃;酸度为pH 6.5;NADH浓度为300μmol/L;丙酮酸浓度为1.2mmol/L。本方法的测定范围为50～1500IU/L,检出限为30IU/L,相对标准偏差2.1%～2.2%(n=10),回收率在96.4%～105%范围内。本方法操作简单,每次测定仅需样品2.0μL、试剂18.0μL,分析速度约为30样/h,利用本方法测定了微量血清中LDH的活性。     

甲基异丁基甲酮萃取石墨炉原子吸收光谱法测定地质样品中的痕量银

建立了石墨炉原子吸收光谱法测定痕量银的方法。研究了仪器工作参数、分离条件及共存离子的干扰,确定了最佳测定条件。结果表明:地质样品经焙烧,用氢氟酸–盐酸–硝酸–高氯酸溶矿,在5%的盐酸介质中加入0.5m L 200 g/L的抗坏血酸溶液及0.25 m L 300 g/L的碘化钾溶液,并以2.0 m L 50 g/L的EDTA溶液掩蔽Cu2+,Pb2+,用2.0 m L甲基异丁基甲酮萃取分离银,在灰化温度500℃、原子化温度2 200℃条件下进行有机相测定。方法检出限为0.084μg/L,测定结果的相对标准偏差为1.89~3.91%(n=6),对国家一级标准物质测定,结果与标准值相符合。     

快速消解–原子荧光光谱法测定大米中总砷

建立快速消解–原子荧光光谱测定大米中砷含量的方法。以硫脲、抗坏血酸的质量浓度均为10 g/L的硫脲–抗坏血酸–盐酸溶液为掩蔽还原剂、10 g/L硼氢化钾溶液溶液为还原剂、盐酸溶液(5+95)为载流,在优化的仪器工作条件下,采用原子荧光光谱法测定,用标准曲线法定量。砷的质量浓度在0.00～10.00 g/L范围内与荧光强度具有良好的线性关系,相关系数为0.999 9,方法检出限为0.7 ng/g。用所建方法对大米样品进行测定,加标回收率为92.1%～104.9%,测定结果的相对标准偏差为0.27%～2.35%(n=5);对两种大米有证标准物质进行测定,测定值均在标准值不确定度范围内,相对误差分别为6.7%和8.3%。该方法精密度、准确度均满足分析要求。     

硫氰酸盐分光光度法测定钨方法的改进

用过氧化钠熔样,在硫酸(1.4mol/L)+盐酸(1.7mol/L)介质中用硫氰酸盐分光光度法测定钨矿石中钨的含量,并对各试剂用量进行了探讨。减少了传统方法中的高浓度盐酸对环境和操作人员造成极大的伤害,测定结果与传统方法的测定结果相吻合。方法用于钨矿石中钨的测定,相对标准偏差为1.2%~8.8%,线性范围为0~18μg/mL,加标回收率为98.89%~100.97%。     

分光光度法测定萃余液中氯仿浓度

用NaOH-吡啶比色法可以测定水或某些废水中的微量CHCl3浓度,但测定N,N-二甲基甲酰胺(DMF)废水经CHCl3萃取DMF后的萃余液中CHCl3浓度时,DMF对显色的有严重的干扰。采用蒸馏预处理后,再用比色法测定蒸馏所得的馏液中CHCl3浓度的方法,可以消除废水中DMF对显色的干扰。研究了水样中DMF浓度、蒸馏汽化率等因素对比色时显色的影响,建立了蒸馏-比色法测定DMF废水萃余液中微量或大量CHCl3浓度的分析方法。对含10g/LDMF水样的测定,CHCl3的线性范围为0～0.75g/L;与顶空色谱法测定结果对比,测定CHCl3浓度为5g/L和0.16g/L水样的相对误差分别为2.1%和1.2%;对CHCl3浓度为0.575g/L的水样进行7次平行测定,相对标准偏差为6.6%。对含DMF<15g/L水样的分析,结果令人满意。     

流动注射-在线富集火焰原子吸收分光光度法测定痕量铅

本文报道在流动注射分析体系中用装有黄原脂棉的微型柱对溶液中Pb2 进行在线富集后,用3.0 mol/L盐酸洗脱柱上富集的Pb2 ,然后采用火焰原子吸收光谱法在线测定痕量Pb2 ,方法的线性范围为0.5～100μg/L。与未富集前相比,测定的灵敏度可提高65倍。方法用于环境水样中痕量Pb2 的测定,回收率在97.0%～102%之间,相对标准偏差小于4.0%,分析结果满意。     

高锰酸钾-甲醛化学发光体系测定甲氧氯普胺

基于在甲醛的作用下,高锰酸钾对甲氧氯普胺的氧化作用而产生化学发光的现象,建立了一种新的用流动注射-化学发光法测定甲氧氯普胺含量的方法.该方法测定甲氧氯普胺的线性范围为0.2~100 mg/L,检出限为0.1 mg/L.对于8 mg/L的甲氧氯普胺标准溶液连续11次测定的相对偏差为1.2%.该方法可用于对制药废水、片剂和针剂中甲氧氯普胺含量的测定.     

Determination of cadmium in spring water by graphite-furnace atomic absorption spectrometry after coprecipitation with ytterbium hydroxide.

A coprecipitation method with ytterbium hydroxide was studied for the determination of cadmium in water samples by graphite-furnace atomic absorption spectrometry. Up to 40 ng of cadmium in water samples was quantitatively coprecipitated with ytterbium hydroxide at pH 8.0-11.2. The concentration factor was 100 fold. The coprecipitated cadmium was sensitively determined without any influence of ytterbium and the calibration curve was linear from 0.1 to 4 ng/mL of cadmium. The detection limit (signal/noise = 2) was 2.9 pg/mL in 100 mL of the initial sample solution. Twenty-nine diverse ions tested did not interfere with the determination in at least a 10000-fold mass ratio to cadmium. The proposed method was successfully applied to the determination of cadmium in spring water.     

Use of the differential pulse cathodic adsorptive stripping voltammetric method for the simultaneous determination of trace amounts of cadmium and zinc

A selective and sensitive method for the determination of cadmium and zinc is presented. The method is based on the adsorptive accumulation of the complexes of Cd(II) and Zn(II) ions with 4-amiono-5-methyl-2.4-dihydro-3H-1,2,4-triazol-3-tion (MMTT) onto hanging mercury drop electrode (HMDE), followed by the reduction of the adsorbed species using a voltammetric scan using differential pulse modulation. The ligand concentration, pH, potential and time of accumulation, scan rate, and pulse height were optimized. Under the optimized conditions, a linear calibration curve was obtained for the concentration of Cd(II) and Zn(II) in the range of 5–450 and 5–850 ng/mL, respectively, with a detection limit of 1.7 ng/mL Cd(II) and 1.3 ng/mL Zn(II). The ability of the method was evaluated by analysis of cadmium and zinc in water and alloy samples The text was submitted by the authors in English.     

Resonance Rayleigh scattering method for the determination of trace amounts of cadmium with iodide-basic triphenylmethane dye systems

In dilute phosphoric acid solution, cadmium (II) reacts with a large excess of I- to form [CdI4]2- which reacts further with basic triphenylmethane dyes such as crystal violet (CV), ethyl violet (EV), methyl violet (MV), brilliant green (BG) or malachite green (MG) to form an ion-association complex. This results in a significant enhancement of resonance Rayleigh scattering (RRS) intensity and the appearance of new RRS spectra. The characteristics of RRS spectra of the ion-association complexes, the influencing factors and the optimum conditions of these reactions have been investigated. The intensity of RRS is directly proportional to the concentration of cadmium from 0 to 60 ng mL(-1) for EV and MV systems, 0 to 80 ng mL(-1) for CV system, and 0 to 100 ng mL(-1) for BG and MG systems. The methods exhibit high sensitivities and the detection limits for cadmium are between 0.35 and 2.00 ng mL(-1) depending on the different reaction systems. The new RRS method was applied to the direct determination of traces of cadmium in pure zinc and synthetic water samples.     

电热蒸发进样低功率MPT—AES测定铜,锌,镉的研究

微波等离子体炬(MPT)是一种具有类似ICP炬管结构的新型等离子体光源,该光源的基本性质已进行了详细的研究。本文采用自制的低功率MPT为激发光源,以氧为工作气体,用微型电热蒸发装置进样,测得铜、锌和镉的检出限分别为3.3、1.4和1.7ng/mL。考察了碱金属元素对铜、锌和镉发射信号的影响,该方法应用于钢样中铜的测定,结果较好。     

Flame atomic absorption determination of trace amounts of cadmium after preconcentration using a thiol-containing task-specific ionic liquid

Dispersive liquid-liquid microextraction (DLLME) based on a task-specific ionic liquid (TSIL) was developed for the extraction and preconcentration of trace amounts of cadmium from aqueous samples, followed by flame atomic absorption spectrometry (FAAS) determination. In the proposed approach, cadmium ions are extracted from aqueous samples using small volumes of trioctylmethylammonium thiosalicylate (TOMATS) dissolved in acetone. TOMATS is a thiol-containing TSIL that can form metal thiolate complexes due to the chelating effect of the ortho-positioned carboxylate group relative to the thiol functionality. The main parameters affecting the performance of DLLME based on TSIL, such as pH, amount of TOMATS, extraction time, injection volume, salt addition, and centrifugation time, were optimized. Under optimum conditions, an LOD of 1.16 ng/mL and a good RSD of 1.8% at 60.0 ng/mL were obtained (n=7). The proposed method was applied to tap water, wastewater, well water, and milk samples. The results showed that DLLME based on TSIL combined with FAAS is a rapid, simple, sensitive, selective, low cost, volatile organic solvent-free, and efficient analytical method for the separation and determination of trace amounts of cadmium ions.     

Ultrasensitive Simultaneous Quantification of Nanomolar Level of Cd and Zn by Cathodic Adsorptive Stripping Voltammetry in Some Real Samples

A novel, simple and sensitive adsorptive stripping voltammetry method was developed for simultaneous determination of Cd and Zn using N‐Nitrozo‐N‐phenylhydroxylamine (Cupferron) as a selective complexing agent. Cadmium and zinc metals gave peaks that were distinctly separated by 450–1200 mV, allowing their determination over a wide range of concentrations. The influence of pH and the nature of supporting electrolytes, concentration of ligand, preconcentration time and applied potential were investigated. The detection limits were 0.058 ng/mL for Zn and 0.092 ng/mL for Cd, and the RSD at a concentration level of 50 ppb, were 1.8–2.1 % for both zinc and cadmium, respectively. The method was applied to the determination of cadmium and zinc in blood, drug, food and water samples with the satisfactory results.     

Solid-phase extraction and determination of ultra trace amounts of lead,mercury and cadmium in water samples using octadecyl silica membrane disks modified with 5,5′-dithiobis(2-nitrobenzoic acid) and atomic absorption spectrometry

A simple and fast method for preconcentration and determination of ultra trace amounts of lead(II), mercury(II) and cadmium(II) in water samples is presented. Lead, mercury and cadmium adsorbed quantitatively during passage of water samples (pH?=?7, flow rate?=?20 mL min^?1) through octadecyl silica membrane disks modified with 5,5′-dithiobis(2-nitrobenzoic acid). The retained lead, mercury and cadmium are then stripped from the disk with a minimal amount of 1 M hydrochloric acid solution as eluent, and determined by atomic absorption spectrometry. The influence of flow rates of the eluent and sample solution, the amount of ligand, type and least amount of eluent, pH of sample, effect of other ions and breakthrough volume are determined. The breakthrough volume of the method is greater than 2000 mL for lead and greater than 1500 mL for mercury and cadmium, which results in an enrichment factor of 200 for lead and an enrichment factor of 150 for both mercury and cadmium. The limit of detection of the proposed method is 177, 2 and 13 ng l^?1 for lead, mercury and cadmium, respectively.     

Preconcentration of Cadmium and Zinc on a Chelating Sorbent and Their Determination by Flame Atomic Absorption Spectrometry

A method is developed for cadmium and zinc preconcentration on a minicolumn packed with a new chelating polymer sorbent. The effects of the test solution pH and volume, the sample matrix composition, the eluent volume, and the sample and eluent flow rates are studied. Zinc and cadmium in the eluate are determined by flame atomic absorption spectrometry. Under optimal conditions, the determined ion recovery is more than 95%. The detection limits (3σ, n = 20) are found to be 15.0 (Cd) and 17.2 (Zn) ng/mL. The developed method is employed for cadmium and zinc determination in samples of seawater and water obtained after oil pumping.     

Determination of cadmium,aluminium, and copper in beer and products used in its manufacture by electrothermal atomic absorption spectrometry

Procedures were developed for determining cadmium, aluminium, and copper in beer and the products used in its manufacture by electrothermal atomic absorption spectrometry. Beer samples were injected into the furnace and solid samples were introduced as suspensions after preparation in a medium containing hydrogen peroxide, nitric acid, and ammonium dihydrogen phosphate for cadmium atomization. Calibration was performed with aqueous standards, and characteristic masses and detection limits were, respectively, 1 and 0.3 pg for cadmium, 18 and 5.4 pg for aluminium, and 5.6 and 6.8 pg for copper. Different samples of beer, wort, brewer's yeast, malt, raw grain, and hops were analyzed by the proposed procedures. Cadmium was found in low concentrations (0.001-0.08 microg/g and 0-1.3 ng/mL); copper (3-13 microg/g and 25-137 ng/mL) and aluminium (0.6-9 microg/g and 0.1-2 microg/mL) were found at higher levels. The reliability of the procedure was confirmed by comparing the results obtained with others based on microwave oven sample digestion, and by analyzing several certified reference materials.     

微波消解-GFAAS法测定菠菜粉和蘑菇粉中微量镉的研究

应用微波消解-石墨炉原子吸收光谱法对菠菜粉和蘑菇粉中微量镉的含量进行测定。菠菜粉和蘑菇粉经HNO3+H2O2微波消解体系消解后,采用磷酸二氢铵作为基体改进剂,灰化温度为900℃,原子化温度为1 350℃,镉含量在0~2 ng/mL范围内与吸光度呈线性关系,线性相关系数为0.999 4,检出限为0.02 mg/kg。该法测定结果的相对标准偏差小于4%(n=6),加标回收率为96.7%~103.2%。