开缝石英管原子化技术的改进

近年来,为提高火焰原子吸收光谱法的灵敏度,先后研究过水冷石英管和开缝石英管(简称缝管)原子化技术.前者使灵敏度提高1～2个数量级^[1～3],后者只提高几倍^[4～6].缝管技术比水冷石英管技术的装置简单,操作方便快速,但因其灵敏度不高,应用受到限制.本文以镉为例,探讨了提高缝管技术灵敏度的途径.     

二步萃取-缝式石墨管原子捕集原子吸收法测定水样中的汞(Ⅱ)

1引言本文研究了水样中的汞（Ⅱ）在DDTC－MIBK体系中的选择性萃取和反萃取；首次采用萃取-缝式石墨管原子捕集火焰原子吸收法测定水样中的汞（Ⅱ），方法富集倍数高、精密度好，干扰少。笔者研制的缝式石墨管火焰原子吸收光谱（FAAS）法测定汞，其灵敏度比相同条件下常规FAAS法和Watting的缝式石英管FAAS法分别高5．5倍和1．1倍。与缝式石英管相比，维式石墨管价廉，导热等性能优良，寿命略长。2实验部分2．1仪器日立180－50型原子吸收分光光度计；汞空心阴极灯，灯电流6mA，波长253．7urn，狭缝2．6urn，空气／乙炔火焰；自制维…     

石英缝管火焰原子吸收法测定食醋中的痕量铅

采用石英缝管装置,辅助火焰原子吸收光谱法测定了食醋中的痕量铅。对铅的测量灵敏度较常规火焰原子吸收法提高了4倍以上。装置简单,方法简便,有效地降低了对测量灵敏度较低的组分的富集要求,提高了分析结果的可靠性。     

原子捕集-火焰原子吸收光谱法测定水中PPb级的银

水冷石英管作原子捕集器用于火焰原子吸收分析早于1976年已有报导。这种原子捕集法可以提高某些元素的灵敏度。Lau等仅报导出这种方法测定银的灵敏度(0.0009ppm),但未给出任何有关实验情况。笔者设计制作了一种简易的不锈钢原子捕集装置。在最佳实验条件下,这种原子捕集-火焰原子吸收法的灵敏度较常规火焰原子吸收法高二个数量级(特征浓度为0.0004ppm),可以测定水中ppb级的银。     

应用微量火焰原子吸收技术测定工业硅中铅

本实验联合应用高性能空心阴极灯，缝式石英管，高效雾化器乙炔－空气火焰原子吸收法，采用了节流脉冲进样测定工业硅中铅，使铅的灵敏度改善了３１倍，同时克服了Ｆｅ，Ａｌ等原子化过程中形成的氧化物吸收石英管壁对实验的影响，此法简便，快速。     

微量火焰原子吸收法测定水中铅

本文研究了高性能空心阴极灯－高效零化－单缝石英管系统这一微量火焰原子吸收技术在微量Ｐｂ测定方面的应用。在Ｐｂ的最灵敏线２１７．０ｎｍ处和次灵敏线２８３．３ｎｍ处考察了微量火焰原子吸收技术对噪音、灵敏度及检出限的改善程度。分别得到噪音改善２．０８倍、３．８６倍；提高灵敏度３２倍、９．９倍；信噪比改善倍数６７和３８的满意结果。选择Ｐｂ的最灵敏线２１７．０ｎｍ测定自来水及合成样品中的Ｐｂ，特征浓度可达６     

原子捕获火焰原子吸收光谱法测定无铅汽油中铅

采用双缝式原子捕获石英管在火焰原子吸收光谱仪上测定无铅汽油中铅含量 ,探讨了原子捕获的机理 ,研究了捕获的时间乙炔流量等测试条件。试验表明 ,方法的灵敏度比GB/T80 2 0 .6 5～ 6 7- 1998中火焰原子吸收光谱法提高了 4倍 ,能测定无铅汽油中 μg·L- 1级的铅含量     

测定心灵丸中痕量铅的喷涂石英管原子吸收光谱法

采用火焰原子吸收光谱法测定中成药心灵丸中的铅。以混合酸消化待分析物，以氘灯扣除背景吸收，采用经钒酸盐溶液喷涂的石英缝管进行测定，考察了样品的预处理方法及提高测定灵敏度和高温下喷涂石英管的抗腐蚀性的机理。结果表明该消化方法可获得澄明的样品溶液而铅没有损失。灵敏度提高了近３倍，检出限为８３７μｇ／Ｌ（σ＝３），ＲＳＤ为０９％～１２％，其回收率为９７９％～１０２３％。     

微量火焰原子吸收技术及其应用

联合应用几种改善火焰原子吸收分析性能的技术可显著地改善火焰原子吸收的灵敏度和检出限,我们称这种方法为微量火焰原子吸收技术。提出了微量火焰原子吸收技术的理论模式。以矿石及其加工产品中微量金的测定和水中铅与砷的测定为例,详细地讨论了微量火焰原子吸收技术的应用效果。联合应用高效雾化器、高性能空心阴极灯、石英缝管和流动注射在线富集的系统,使测定微量金的信噪比改善950倍,检测限达到0.2ng/ml(3σ),可以测定矿石及其加工产品中0.005g/t以上的金。联合应用高效雾化器、高性能空心阴极灯和石英缝管的系统,使测定铅的信噪比改善67倍,检测限达1.6ng/mL(3σ),可以直接测定水体中ng/ml级的铅。采用联合应用高性能空心阴极灯、石英缝管和HG-3简易氢化物发生器的系统,使测定砷的信噪比改善了430倍,检出限达3.0ng/ml(3α),可以直接测定水体中ng/ml级的砷。     

镉的原子捕集-火焰原子吸收光谱分析

水冷石英管作为捕集器应用于火焰原子吸收光谱分析近年来已有报导,T,S,West等人作了较系统的研究。原子捕集是一种在火焰中浓缩待测原子的予富集技术,它与化学分离富集技术相比较,避免了化学前处理及操作带来的污染和损失,保留了火焰原子吸收法的优点,并由于捕集提供了极高的原子密度,因而大大地提高了测量的灵敏度。对甘蓝中的微量镉进行了测定,检出限为0.008μg/ml,变异系数为2.9％。     

Applications of a slotted tube atom trap and flame atomic absorption spectrometry: Determination of tin in copper-based alloys after hydride generation

A sensitive system is reported for the determination of tin in copper-based alloys by flame atomic absorption spectrophotometry. Use of a slotted quartz atom trap coupled with hydride generation improved the sensitivity by a factor of 200, compared with that obtained using conventional flame AAS. The determination of tin in a series of reference samples demonstrates the usefulness of the system for the analysis of metallurgical samples.     

在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收法测定水中痕量镉和铜

应用高效的在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收系统直接测定水中痕量镉和铜 ,试验用内装 2 0 0 mg Amberlite XAD- 4键合的 5-磺酸 - 8-羟基喹啉螯合树脂的锥形柱 ,在 p H6条件下 ,样品流速为 6.0 ml·min-1,90 s装样 ,用 0 .5mol· L-1HCl洗脱 ,分析速度为30样·h-1分别获得 38和 40倍的富集 ,经石英缝管增敏 ,总灵敏度分别提高 1 36和 1 2 0倍 ,检出限为 0 .1和 0 .2μg· L-1。对镉和铜含量分别为 2 .0 ,5.0μg· L-1的水样连续测定 1 1次的相对标准偏差分别为 2 .8%和 3.4% ,可直接测定水体中 μg· L-1级的镉和铜。     

The determination of tin in zirconium alloys using slotted atom trap (STAT) flame atomic absorption spectrophotometry

Summary An improved system is reported for the determination of tin in Zircaloys by flame atomic absorption spectrophotometry. Use of a slotted quartz tube atom trap improved sensitivity and precision by a factor of 2–3 compared to that obtained by conventional flame AAS. Determination of tin in reference Zircaloys proves the good precision and accuracy of the proposed analytical procedure.     

Sensitivity enhancement in flame atomic absorption spectrometry for determination of copper in human thyroid tissues.

Various designs of quartz tube in a slotted tube atom trap were examined for improving the sensitivity of flame AAS. A 3.5-fold enhancement in the sensitivity was obtained by using the optimized method. The method was applied to the determination of Cu in cancerous and non-cancerous human thyroid tissues. The Cu concentrations of the cancerous samples tended to increase compared with the non-cancerous samples. Zn concentrations of the same tissues were also determined.     

Application of the slotted quartz tube in flow-injection flame atomic-absorption spectrometry

The slotted quartz has been applied to flow-injection flame atomic-absorption spectrometry (FI-FAAS) showing several important advantages. The tube life was improved by a factor of 5-6 compared to conventional continuous aspiration. Flow impact systems were found not to be necessary in the applications so that larger enhancement factors may be achieved without sacrifice in precision. For 1.0 mg/l. copper, 1.0 mg/l. lead, 0.1 mg/l. cadmium and 1.0 mg/l. gold sensitivity enhancement factors of 3.1, 5.5, 5.3 and 4.0 were obtained with precisions of 1.3%, 1.1%, 1.6% and 1.7% RSD (n = 11) respectively. Application of the slotted quartz tube FI-FAAS method to the determination of heavy metals in urine has shown improved tolerance to interfering matrices. Recoveries obtained by spiking undiluted urine samples with 0.1 mg/l. copper and lead, and 0.01 mg/l. cadmium were in the range 100-102%.     

In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies

Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FAAS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 μg mL^− 1 and 0.51 ng mL^− 1, respectively. Linear calibration plot was obtained in the range of 2.5–25.0 ng mL^− 1 for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e.     

Determination of Bismuth in Bottled and Mineral Water Samples at Trace Levels by T-Shaped Slotted Quartz tube-Atom Trap-Flame Atomic Absorption Spectrometry

An accurate and reliable analytical method for the determination of bismuth at trace levels in bottled and mineral water samples has been developed based on hydrogen assisted T-shape slotted quartz tube-atom trap-flame atomic absorption spectrometry (T-SQT-AT-FAAS). Conventional FAAS is not sufficiently sensitive to measure trace and ultra-trace levels of metals due to the low nebulization efficiency and short residence time of atoms in the light path. To overcome this problem, atom trapping with a T-shaped slotted quartz tube was coupled to the FAAS system. Bismuth atoms were trapped on the surface of T-SQT and released by hydrogen gas, which provided a reducing environment. All of the system parameters such as flame type, hydrogen flow rate, the height of T-SQT from the burner head, and trapping period were optimized to enhance the analytical signal to attain low detection limits. After obtaining the optimum conditions, the limit of detection and limit of quantitation of the developed method were found to be 0.95 and 3.2?µg L^?1, respectively. Recovery values were obtained between 90% and 104% that showed good accuracy and applicability of the proposed method to the analysis of bottled and mineral water samples.