TOPO化学修饰电极电富集-石墨炉原子吸收法测定水中痕量Cr(Ⅵ)的研究

在钨丝盘电极上修饰一层TOPO,用此电极对水中痕量Cr(Ⅵ)进行预富集,再放入石墨杯中进行原子吸收法测定,利用化学修饰电极的络合、富集作用和原子吸收法测定高选择性,获得满意的结果。富集底液选用1mol.dm-3HC1,测定线性范围为0.5～20ng/ml,在含Cr(Ⅵ)量为10ng/ml溶液中十次测定值的变异系数为3.9％,检出下限为0.3ng/ml,二十多种共存离子不干扰测定。     

三辛基氧化膦化学修饰电极预富集-石墨炉原子吸收测定水中痕量锑的研究

本文研究了三辛基氧化膦(TOPO)化学修饰电极预富集石墨炉原子吸收法测定水样中痕量锑。水中痕量锑被电解还原蓝电积在TOPO修饰的钨电极上,然后放入石墨杯中直接原子化。锑的测定线性范围1.0—20ng/mL,含10ng/mL锑的溶液九次平行测定,变异系数为3.1％,捡出限为0.1ng/mL,24种共存离子及有机物不干扰测定。方法灵敏、简便、并用于一些水样的测定,得到满意的结果。     

化学修饰硅胶预富集—石墨炉原子吸收法测定水中痕量汞

本文提出了用化学修饰硅胶预富集-石墨炉原子吸收法测定水中痕量汞的方法,讨论了二硫氨基甲酸修饰硅胶的制作和方法的测试条件。该法操作简便、快速、灵敏。100ml水样经预富集后,最低检出限为0.l0ng/ml,其相对标准偏差为4.1％。对四种不同水样的测定,回收率在96.5-107.5％之间。     

以甲壳素为母体的螯合树脂预富集-悬浮液进样GFAAS法测定水中痕量银的研究

报道了螯合树脂 PCON (N,N-二乙基胺基环硫丙烷交联壳聚糖)对银的分离、富集作用,富集物以悬浮液进样,石墨炉原子吸收法测定。结果表明PCON 螯合树脂用 5% 盐酸清洗后,在 pH11.0±0.2 范围内,富集效果高达 98.8±1.0% ,银的浓度在 0.2～2.0ng/mL 范围内,PCON 螯合树脂富集效率不受银量的影响,在超声波振荡下,4min 即达到富集平衡,本方法已用于自来水中痕量银的测定。     

石墨炉原子吸收法测定高纯硒中痕量铁

研究了石墨炉原子吸收直接进样法和石墨炉内富集法测定高纯硒中痕量铁的条件,建立了石墨炉原子吸收法直接测定高纯硒中痕量铁的分析方法.直接进样法的检出限为0.008 μg/g,石墨炉内富集法的检出限为0.004 μg/g,相对标准偏差分别为:5.2%和4.6%,两种方法检测样品结果基本一致.测定含铁0.3 μg/g的高纯硒,测定值的RSD为4.6～5.2%.     

痕量铅在Nafion修饰电极上的离子交换及其测定的研究

本文利用Nafion膜与试液中的痕量铅进行离子交換的特性,建立了Nafion修饰电极的富集及测定铅的方法,并探讨了Nafion修饰电极作用机理。本方法测定Pb~(2+)的线性范围为13～133ng/mL,变异系数为3.5％,检测下限为6ng/mL。     

二苯硫脲-醋酸丁酯萃取-石墨炉原子吸收法测定地球化学样品中痕量银

对石墨炉原子吸收光谱法测定地球化学样品中痕量银进行了研究。样品经盐酸、硝酸、硫酸、高氯酸溶解,在盐酸(1.2mol/L)介质中用醋酸丁酯萃取银与二苯硫脲螯合物,用石墨炉原子吸收光谱法测定地球化学样品中痕量银,方法检出限为0.011ng/mL,相对标准偏差(RSD,n=11)为6.0%~12.2%,加标回收率为96.00%~105.00%。能满足地球化学样品中银含量为0.02~5μg/g范围内银测定的准确度和精密度的要求。     

冠醚壳聚糖多孔微球选择性富集-石墨炉原子吸收法测定绒柄牛肝菌中的痕量铅

报道了用冠醚壳聚糖多孔微球选择性富集绒柄牛肝菌中痕量铅并用石墨炉原子吸收法测定.DB-18-crown-6-CTS多孔微球在pH5.5时,对Pb2+的富集率达到98%.吸附的Pb2+能用5 mL 2 mol/L的HCl定量洗脱,洗脱率98.1%.Pb2+被洗脱后,用石墨炉原子吸收法测定.该方法的富集倍数为100倍,检出限(3σ)为0.085μg/L,相对标准偏差小于2.8%,用于分析绒柄牛肝菌样品,回收率为94.5%～102%.     

二苯硫脲-醋酸丁酯萃取-石墨炉原子吸收法测定地球化学样品中痕量银

对石墨炉原子吸收光谱法测定地球化学样品中痕量银进行了研究。样品经盐酸、硝酸、硫酸、高氯酸溶解,在盐酸(1.2mol/L)介质中用醋酸丁酯萃取银与二苯硫脲螯合物,用石墨炉原子吸收光谱法测定地球化学样品中痕量银,方法检出限为0.011ng/mL,相对标准偏差(RSD,n=11)为6.0%¹2.2%,加标回收率为96.00%12.2%,加标回收率为96.00%¹05.00%。能满足地球化学样品中银含量为0.02105.00%。能满足地球化学样品中银含量为0.02⁵μg/g范围内银测定的准确度和精密度的要求。     

冠醚壳聚糖多孔微球选择性富集-石墨炉原子吸收法测定雨水中痕量铅的研究

报道用冠醚壳聚糖多孔微球选择性富集雨水中痕量铅并用石墨炉原子吸收法测定.DB-18-crown-6-CTS多孔微球在pH 5.5时,对Pb2+的富集率达到98%.吸附的Pb2+能用5 mL 2 mol·L-1的HCl定量洗脱,洗脱率98.1%.Pb2+被洗脱后,用石墨炉原子吸收法测定.该方法的富集倍数为100倍,检出限(3σ)为0.085 μg·L-1,相对标准偏差小于2.75%,用于分析实际雨水样,回收率为94.5%～102%.     

Adsorptive voltammetric determination of copper with a benzoin oxime graphite paste electrode

A method for the determination of trace amounts of copper with a chemically modified carbon press-formed electrode is described. Copper could be accumulated at the electrode by complexing with benzoin oxime in ammonia buffer, then reduced at a constant potential of −0.4 V (vs. SCE) in nitric acid solution. Finally, a well-defined stripping peak could be obtained by scanning the potential in a positive direction. The response depends on the concentration of copper and accumulation time. For an accumulation time of 5 min the detection limit is about 1 ng/ml and the linear range is from 2 ng/ml to 4000 ng/ml, with a relative standard deviation of 5%. Many common metal ions have little or no effect on the determination of copper. The recommended procedure was applied to the determination of trace amounts of copper in natural water, and the results are in agreement with those of atomic-absorption spectrometry.     

石墨炉原子吸收光谱法测定中药漏芦中微量铅

中药漏芦具有抑制动脉粥样硬化、抗脂质过氧化、减弱血小板聚集和提高免疫力等作用[1]。测定中药中微量元素的含量,对于探讨中药药理、提高药效和降低毒副作用有重要的意义[2,3]。铅是一种毒性元素,它在人体中具有累积性,通过肠胃道吸收,严重损害神经系统、造血系统和消化系统,从而导致肌体免疫力降低。本文选用磷酸氢二铵为基体改进剂,采用石墨炉原子吸收光谱法,对漏芦中Pb的含量进行了测定,考察了影响测定结果的主要因素。样品分析结果表明,本法简便、快速、灵敏、准确。1　实验部分1 1　仪器及工作条件180 80型原子吸收分光光度计、…     

A new method for the voltammetric determination of nitrite

A voltammetric method is presented for the determination of nitrite by use of a carbon-paste electrode chemically modified with an anion-exchanger. Because it is possible to accumulate nitrite on the electrode surface, trace nitrite concentrations down to 1 ng/ml can be determined.     

石墨炉原子吸收光谱法测定大鼠血清中硒

通过考察不同基体改进剂效果，提出了以硝酸锶和硝酸钯做为混合基体改进剂。建立了用石墨炉原子吸收法测定牛血清和大鼠血清中痕量硒的分析方法。线性范围为0-120ng/mL，硒的检出限为0．095ng／mL，方法用于标准牛血清测定。结果与标准值基本吻合，大鼠血清测定标准加入回收率为102％。     

Determination of trace amounts of gold in waste water by graphite furnace atomic-absorption spectrophotometry with preconcentration on trioctylphosphine oxide chemically modified tungsten wire matrix

Preconcentration on a trioctylphosphine oxide (TOPO) chemically modified tungsten wire matrix followed by graphite furnace atomic-absorption spectrophotometry measurement is described for the determination of trace gold in waste water. The TOPO modified tungsten wire matrix, after accumulating the gold, is placed in a graphite cup for direct atomization and measurement. Under the selected conditions, the absorbance is proportional to the concentration of gold over the range 0.4-18 ng/ml and the detection limit is 0.2 ng/ml. This method is sensitive and convenient. It has been applied to some waste waters with satisfactory results.     

Preconcentration of trace silver with yeast for river water analysis

A new preconcentration method with yeast is presented. The method was evaluated for the determination of trace silver in river waters by graphite furnace atomic absorption spectrometry (GFAAS). A suitable cultivation bed for preconcentration of silver was 1.75 mg ml-1 2-ammonium hydrogen phosphate. The optimal cultivation time and temperature were 2 h and 25 degrees C. Under optimal conditions, silver in aqueous sample was concentrated to 6.9-fold by yeast. The detection limit was 4.6 pg ml-1 (3S/N) for silver in river water. The yeast preconcentration method was applied to the determination of silver in river waters. The recovery of spiked silver was in the range of 89 to 110%. By the preconcentration, it was found that ultra trace silver in river waters could be determined without interferences of matrix elements, after only the cultivation and with no chemical treatment.     

Determination of theophylline in tea and drug formulation using a Nafion(R)/lead-ruthenium oxide pyrochlore chemically modified electrode

Square-wave voltammetry was used for the determination of trace amounts of theophylline in tea and drug formulation at a Nafion(R)/lead-ruthenium oxide pyrochlore chemically modified electrode. This chemically modified electrode exhibits a marked enhancement of the current response compared to a bare glassy carbon electrode. The calibration graph for the determination of theophylline was linear up to 100 muM in 0.1 M, pH 3 phosphate solution with a detection limit (S/N=3) of 0.1 muM. The results of 15 successive repetitive measurement-regeneration cycles showed a relative standard deviation of 1.3% for 10 muM theophylline indicating that the electrode renewal gives a good reproducible surface. Quantitative analysis was performed by the standard addition method for the theophylline content in commercially available tea and drug.     

水中痕量汞的半微分阳极溶出分析

本文提出了测定痕量汞的半微分阳极溶出伏安法。玻碳电极用2,2’-联吡啶乙醇溶液进行修饰后再电镀—层金膜。支持电解质为0.1mol/HCl,修饰电极的重现性和灵敏度优于未修饰电极。讨论了予电解电位、予电解时间、电极转速和支持电解质的影响。溶出峰高与汞浓度在0.2～60ng/ml范围内呈良好线性关系,检测下限为0.11ng/ml。本法已用于自来水、雨水和深井水中汞的测定,获得满意结果。     

Determination of trace amounts of silver with a chemically modified carbon paste electrode

A method for the determination of trace amounts of silver with a chemically modified carbon paste electrode is described. The modified electrode is prepared by simply mixing a chelating resin (a polythioether backbone and dioxymonosulphur polyethylene polyimines in the side-chain polymer) with graphite powder and Nujol oil. By immersing the electrode in a silver sample solution (pH = 6.5–7.5), silver can be adsorbed on the electrode surface and then determined by voltammetry in a separate blank solution. The response depends on the concentration of silver and the preconcentration time. For a preconcentration time of 5 min, the detection limit is about 3 × 10^?10 M and the linear range is from 5 × 10^?10 to 1 × 10^?7 M with a relative standard deviation of 4%. Many common metal ions have no or little effect on the determination of silver. The recommended procedure was applied to the determination of trace amounts of silver in waste water.