钨丝电热蒸发-氩/氢火焰原子吸收光谱分析方法

基于钨丝电热蒸发设备,建立了一种全新的钨丝电热蒸发-氩/氢火焰串联原子吸收光谱系统.研究了系统抗酸、抗盐能力,结果表明:Na<'+>和Ca<'2+>质量浓度小于400 mg/L、Mg<'2+>质量浓度小于1500 mg/L时不干扰测定.在优化的仪器条件下:Pb、Cd、Au和Ag的检出限分别为:0.016、0.0005、...     

异相Fenton可见光降解微囊藻毒素-LR机理的研究

在可见光照射下(λ>450 nm),以负载Fe<'2+>的NaY分子筛制备得到Fe<'2+>-NaY催化剂(简称FeY),研究了FeY/H<,2>O<'2>降解微囊藻毒素-LR(MC-LR)的机理,发现在宽pH范围内,Vis/FeY/H<,2>O<,2> 体系对MC-LR降解率大于90%.采用 LC-MS跟踪分析降解中...     

新型荧光增强法检测水样品中碘离子

Hg2+可以猝灭核黄素的荧光,碘离子(I-)可以与Hg2+形成HgI2,基于此,发展了一种新型的荧光增强法检测水中I-的方法。Hg2+加入后,核黄素在525 nm处的荧光被猝灭;继续在体系中加入不同浓度的I-,体系中Hg2+被不断消耗,导致核黄素在525 nm处的荧光逐渐增强。该方法检测I-的线性范围在1-100μmol·L-1,检测限是0.4μmol·L-1;同时,该方法具有较快的响应时间(2 min);对其他卤素离子具有较好的选择性;用于水中I-检测时得到了较好的回收率。     

微波消解-零交截距导数分光光度法同时测定催化剂中钴和镍

采用微波法消解催化剂 ,研究确定了微波消解催化剂的最佳工作条件。应用零交截距导数分光光度法解决了 PAR- CO2 +、PAR- Ni2 +体系中 Co2 +、Ni2 +的同时测定。钴和镍的线性范围分别为 0～ 30 μg/ 2 5m L和 0～ 2 5μg/ 2 5m L,催化剂样品中钴和镍测定结果的相对标准偏差 (n=5)分别≤ 1 .5%和≤ 1 .0 % ,与标准值相对误差分别≤± 1 .5%和≤± 2 .1 %。本方法测定催化剂中钴和镍 ,酸用量少 ,降低了环境污染     

湿法消解-原子吸收光谱法测定啤酒中痕量铅和锌

研究了用湿法消解啤酒样品、石墨炉原子吸收光谱(GFAAS)及火焰原子吸收光谱(FAAS)法分别测定啤酒中的痕量Pb2+和Zn2+。对仪器的工作参数进行了优化,探讨了混合酸消解体系、消解液用量,消解温度等因素的影响。结果表明,在200℃温度下,HNO3+HClO4(16+4)混酸能完全消解样品。Pb2+、Zn2+分别在0～80μg/L、0～1.50μg/mL范围内线性关系良好(线性相关系数r分别为0.9995和0.9997),其检出限分别为0.2μg/L、8.0μg/L。测定Pb2+、Zn2+的相对标准偏差(RSD)分别为1.8%和0.92%,加标回收率分别为96.5%和99.8%。该方法检出限低,精密度和准确度高,适用于啤酒样品中痕量铅、锌含量的测定。检测的9种啤酒样品中铅、锌含量范围分别为11.34～47.15μg/L、277～422μg/L,低于食品中的限量值。     

氧化锌纳米棒光电极对核黄素的光致电化学响应及应用

基于核黄素在第二工作电极上的预还原,将还原型核黄素作为电子给体纳入氧化锌纳米棒光电极的光致电化学反应过程,构建了一种新的光致电化学反应系统.优化了电化学制备氧化锌纳米棒光电极的方法,研究了核黄素与氧化锌纳米棒光电极的光致电化学反应机理,建立了一种测定核黄素的光致电化学分析法.在p H=6.5的缓冲溶液中,以玻碳电极为预还原电极,在峰值波长为365 nm、能量为450μW/cm~2的光照下,在偏压0.1 V处测得的光电流与1.00×10~(-5)~1.00μmol/L核黄素浓度的对数值成正比,检出限为6.0×10~(-7)μmol/L(S/N=3),灵敏度为195.6 n A/lg[c(μmol/L)].对实际样品测定的相对标准偏差小于6.25%,回收率为99.0%~104%,常见生化物质对核黄素光电流的响应无干扰.     

微乳液介质–PAR显色体系光度法测定油中的Co~(2+)

采用微乳液为介质,以4-(2-吡啶偶氮)–间苯二酚(PAR)为显色剂,在乙酸–乙酸钠缓冲体系中,利用分光光度法测定油样中的微量Co2+。Co2+与PAR形成稳定的橙红色络合物,其最大吸收峰位于518 nm处,Co2+含量c在0～25μg/(25 mL)范围内服从比耳定律,线性回归方程为A=0.042 02c+0.004 46,相关系数为0.999 5。以该方法测定辽河重油和辽河渣油中钴Co2+的含量,其相对标准偏差分别为1.73%和2.22%(n=6),回收率分别为102.60%和97.67%,检出限为0.13μg/(25 mL)。研究结果表明,该方法不需分离可以直接测定油样中的Co2+,具有经济适用,简单易行,灵敏度、准确度高,选择性好等特点。     

亚硫酸氢钠-过氧化氢超微弱化学发光体系用于核黄素检测

亚硫酸氢钠(Na HSO3)和过氧化氢(H2O2)反应可产生微弱的化学发光。核黄素对亚硫酸氢钠和过氧化氢的化学发光有极大的增强作用,且化学发光强度在0.02~2.0μg/m L范围内与核黄素浓度呈良好的线性关系。据此,建立了核黄素的高灵敏化学发光分析方法,方法检出限为0.007μg/m L,相对标准偏差(n=11)不大于1.6%。利用荧光光谱、化学发光谱对核黄素增强Na HSO3-H2O2体系化学发光的机理进行探讨,为该体系的应用研究提供了新思路。     

Ni2+-胆红素和Ni2+-2,2'联吡啶-胆红素的单扫描极谱研究

本文研究了Ni²⁺-胆红素和Ni²⁺-2,2'联吡啶-胆红素在微碱性介质中的单扫描极谱行为和电极反应机理.在Ni²⁺-胆红素体系中.于-1.0V处产生络合物的催化前波;而在Ni²⁺-2,2'联吡啶-胆红素体系中,则于-1.5V处产生催化氢波.这2个体系的线性范围分别为1×10^-6～5×10^-6mol/L和2×10^-7～8×10^-6mol/L.     

核黄素化学发光体系测定盐酸赛庚啶

核黄素是一种荧光试剂,本实验发现,核黄素也可以用作化学发光试剂.以核黄素为化学发光试剂, 构建了NCS-核黄素-盐酸赛庚啶化学发光新体系.利用此体系建立了测定盐酸赛庚啶的化学发光分析新方法.方法的线性范围为0.02～1.0 mg/L, 检出限为9.0 μg/L, 对浓度为01 mg/L盐酸赛庚啶溶液进行11次平行测定的相对标准偏差(RSD)为0.8%.此法已用于药品中盐酸赛庚啶含量的测定, 结果与药典测定结果一致.对化学发光反应的机理也进行了初步的探讨.     

Direct flame solid sampling for atomic absorption spectrometry: determination of copper in bovine liver

In this work a new device for the direct introduction of solid samples into flame atomizers is proposed. The determination of copper in bovine liver reference material by flame atomic absorption spectrometry (FAAS) using a conventional air–acetylene flame was chosen as an example. Between 0.05 and 0.50 mg of the test sample was weighed directly into a small polyethylene vial connected to a glass chamber. A flow of air carries the test sample as a dry aerosol to a T-shaped quartz cell positioned above the burner in the optical path. The atomic vapor generated produces a transient signal of less than 3-s duration; integrated absorbance is used for signal evaluation. Optimized conditions for air flow rate, flame stoichiometry, etc., were evaluated. There was no statistical difference between the results from the proposed system, compared with those obtained by prior sample digestion and determination by conventional FAAS. No excessive grinding of the samples was required and samples with particle size less than 80 μm were used throughout. Background signals were always low and a characteristic mass of 1.5 ng was found for Cu. The proposed system allows the determination of 60 test samples in 1 h and it can be easily adapted to conventional atomic absorption spectrometers.     

火焰原子吸收光谱法测定高铋铅中的铜

建立了火焰原子吸收光谱法测定高铋铅中铜含量的方法。研究了多种溶样方法,最终采用硝酸-酒石酸溶解试样,在硝酸(10%)介质中以火焰原子吸收光谱法测定溶液中的铜量,加标回收率在99.4%~105%,相对标准偏差(RSD,n=7)小于3.5%。方法操作过程简单,精密度高,回收率良好,能够较好地满足分析检测的要求。     

Use of masking agents in the determination of lead in tap water by flame atomic absorption spectrometry with flow injection pre-concentration

The selectivity of immobilised 8-hydroxyquinoline for lead is shown to be improved by the use of masking agents during pre-concentration, prior to determination by flame atomic absorption spectrometry. Interference by iron, copper, aluminium and zinc is suppressed by including triethanolamine, thiourea, fluoride, acetylacetone or cyanide in the buffer as masking agents. Species such as iron or copper can completely prevent the pre-concentration of lead. This is shown to be overcome by using a buffer consisting of 0.2 M boric acid, 2% triethanolamine, 2% thiourea and 2% acetylacetone, even when the interfering species is in a 200-fold excess over lead. Recoveries from tap water samples, to which various amounts of lead had been added, ranged from 94 to 108%. Results of analyses of tap water samples using this method were in good agreement with those obtained by electrothermal atomic absorption spectrometry.     

Comparison of electrothermal atomic absorption spectrometry of the metal content of sewage sludge with flame atomic absorption spectrometry in conjunction with different pretreatment methods

Determination of the metal content of sewage sludges is of increasing importance in order to assess the suitability of the sludge for disposal to agricultural land. The methods currently used for the determination of cadmium, chromium, copper, nickel, lead and zinc are time-consuming. A rapid electrothermal atomic absorption procedure with homogenization as the only pretreatment is compared with wet and dry pretreatment methods followed by flame atomic absorption spectrometry, in a statistically designed experiment. The precision of the rapid electrothermal atomic absorption procedure compares well with flame atomic absorption in conjunction with all pretreatment methods used. Time saved by the use of this method is substantial; the procedure could be used advantageously for routine analysis.     

热喷雾进样火焰原子吸收光谱法测定河水中的铅

铅被广泛应用于蓄电池、建筑材料、电缆外套等工业生产中,是造成河水污染的主要原因。铅为生物体有害元素,当其被人体组织吸收后,分布予肝、肾、肺、脑中,损害骨髓造血系统和神经系统。在环境检测中铅是必须检测的元素之一。火焰原子吸收光谱法具有仪器简单、操作方便、抗干扰能力强、稳定性好等特点,但由于雾化效率低和灵敏度低,不能直接用于测定样品中的低含量铅。     

火焰原子吸收光谱法测定粗锌中的铜

建立火焰原子吸收光谱法测定粗锌中的铜含量。采用硝酸–酒石酸溶解样品,并以其为测定溶液介质,检测波长为324.7 nm,以水为参比,采用空气–乙炔火焰以原子吸收光谱仪进行测定。在优化的实验条件下,铜的质量浓度在0.10~2.50μg/m L范围内与吸光度有良好线性关系,相关系数为0.999 7,方法检出限为0.01μg/m L。测定结果的相对标准偏差为1.0%~3.0%(n=11),样品加标回收率为97%~102%。该方法具有灵敏度高,干扰少,重现性好等优点,适用于铜含量在0.001%~0.50%之间的粗锌中铜的测定。     

Determination of lead in copper based alloys using a modified quartz tube atom trap and flame atomic-absorption spectrometry

Summary Studies have been carried out on a series of quartz tube atom traps designed to increase the sensitivity of the flame atomic absorption spectrophotometry for lead. A significant improvement has been achieved and is illustrated by the determination of lead in copper based alloys.

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Bestimmung von Blei in Kupferlegierungen mit Hilfe der Flammen-AAS und einer modifizierten Quarzrohrfalle

     

The sequential injection system with adsorptive stripping voltammetric detection

Two sequential injection systems have been developed for adsorptive stripping voltammetric measurement. One is for substances adsorbing at mercury, e.g. riboflavin. In this case, a simple arrangement with only sample aspiration is needed. Reproducibility was 3% and detection limit 0.07 μM. The measuring system was applied to determination of riboflavin in vitamin pills and to study the photodegradation process of riboflavin in aqueous solutions. In the second case, metal ions were determined. They have to be complexed before deposition on the mercury surface. Thus, both the sample and the ligand have to be aspirated in the system. In this case, the reproducibility was ≈6% and the detection limit <0.1 ppm for cadmium, lead and copper when complexation with oxine was used. Dimethylglyoxime was used in determination of nickel and cobalt and nioxime complexes were used in determination of nickel and copper. With these complexing agents, the reproducibility was the same as with oxine, but the metals could be determined at concentrations lower than 0.01 ppm. Application of two ligands in a SIA system with AdSV detection was also studied. Simultaneous determination of copper, lead, cadmium and cobalt was possible by using oxine and dimethylglyoxime. Copper and nickel were simultaneously determined by using dimethylglyoxime and nioxime.     

Flame atomic absorption spectrometric determination of lead in waste water and effluent after preconcentration using a rapid coprecipitation technique with gallium phosphate

A determination method for lead in waste water and effluent was studied using flame atomic absorption spectrometry after preconcentration of lead by the rapid coprecipitation technique with gallium phosphate. Lead ranging from 0.5 to 50 microg was quantitatively coprecipitated with gallium phosphate from 100-150 mL sample solution (pH approximately 5). The presence of gallium phosphate did not affect the atomic absorbance of lead. Since the concentration of gallium in the final sample solution is also measurable by flame atomic absorption spectrometry at 250.0 nm without further dilution, the rapid coprecipitation technique, which does not require complete collection of the precipitate, becomes possible using a known amount of gallium and measuring the concentrations of both lead and gallium in the final sample solution by flame atomic absorption spectrometry. The 32 diverse ions tested gave no significant interferences in the lead determination. The method proposed here is rapid and has good reproducibility.     

Determination of copper in medicinal plants used as dietary supplements by atomic absorption spectrometry with direct flame solid analysis

An alternative device for the direct solid analysis (DSA) for copper determination by flame atomic absorption spectrometry (FAAS) is proposed. Copper was directly determined in commercial medicinal plants used as dietary supplements. The determination of copper in solid samples by DSA–FAAS was made by using a conventional air–acetylene flame. Between 0.05 and 1.5 mg of each test, sample was weighed directly into a small polyethylene vial connected to the device used for solid introduction into the flame. Test samples were introduced into the flame as a dry aerosol using a T-quartz cell set between the burner and the optical path. The T-quartz cell has a slit in the superior part by which the solid aerosol passes to the flame. A transient signal, evaluated as integrated absorbance, is produced and it is totally integrated in 2 s. Background signals always presented absorbance values less than 0.1. It was found a characteristic mass of 0.8 ng Cu and absolute limit of detection of 1.2 ng (3 s), or 1.2 μg g⁻¹ if a sample mass of 1 mg was used. Optimized conditions for air flow rate, flame stoichiometry, and so on were established as well. No excessive grinding of the samples was needed and samples with particle of size less than 80 μm were used throughout. No statistical difference between the results from the proposed system and those obtained by sample digestion and determination by conventional FAAS was observed. With the proposed procedure, more than 50 test samples can be analyzed in 1 h and it can be easily adapted to conventional spectrometers for FAAS.