石墨炉原子吸收光谱法测定土壤中有效钼

钼是植物生长必需的微量元素之一,尤其是豆科植物和十字花科植物,对钼有较大的需要量,因此测定土壤中有效钼对农业生产有重要意义.测定土壤中有效钼的方法有比色法和极谱法测定[1-2],比色法需经萃取分离富集,极谱法也需预先分离除去铁、锰等大量干扰元素,分离富集手续冗长,在极谱法中,工作人员还需与毒性很强的汞接触.火焰原子吸收光谱法测定土壤中钼,由于灵敏度较低,需经分离富集后才能提高灵敏度.本工作用石墨炉原子吸收光谱法测定土壤中有效钼,浸取液不需分离直接进样测定,可省去冗长的分离富集操作,避免工作人员与汞的接触.     

火焰原子吸收光谱法测定矿石中微量钼

矿石中钼的测定方法有分光光度法、原子吸收光谱法、电感耦合等离子体原子发射光谱法和X射线荧光光谱法等[1-4]。在这些方法中用常规的火焰原子吸收光谱法测定矿石中钼,由于钼很难被原子化,测定灵敏度很低,且地质样品中共存元素的干扰非常严重[5],一般很难测定。本工作用4种酸溶解     

甲基异丁基甲酮萃取-火焰原子吸收光谱法测定氧化锑中的磷

研究了MIBK萃取-火焰原子吸收光谱法测定氧化锑中的磷。在盐酸介质中,磷酸根与钼酸铵形成磷钼物质的量之比为1∶12磷钼杂多酸,用酒石酸钾钠掩蔽锑,以甲基异丁基甲酮为萃取试剂,用火焰原子吸收光谱法测定有机相中磷钼杂多酸中的钼,据此建立了一种间接测定氧化锑中微量磷的新方法。在优化的实验条件下,当磷的含量在0.055~1.00 mg/L范围内时,其吸光度与浓度呈良好的线性关系;方法的检出限为0.011 mg/L;对4个样品进行测定的回收率在97.8%~106.2%之间;相对标准偏差为2.6%~4.2%。用于氧化锑中微量磷的测定,结果满意。     

电感耦合等离子体质谱(ICP-MS)法测定土壤中的有效钼

准确快速测定土壤中的有效钼,是评价土壤肥力的重要指标,对指导作物生产有重大意义。本文采用草酸-草酸铵溶液浸提土壤样品,待测浸提液稀释5倍后通过电感耦合等离子体质谱法在氦气模式下测定土壤中有效钼的含量,建立了土壤中有效钼高灵敏度分析的检测方法。选择103Rh为内标元素,校正仪器在测定过程中引起的信号飘移。对两种前处理方式进行比较,确定了震荡30 min、放置过夜的浸提方法浸提效果更好且更利于大批量样品的分析。使用震荡30 min、放置过夜的浸提方法对5个土壤标准物质有效钼进行前处理,其测定值均在标准值范围内;分别在无气体模式和氦气模式下比较了浓度为0mg/L、1mg/L、2mg/L、5mg/L、10mg/L、50mg/L的Mn对5ug/L 95Mo测定浓度的影响,结果表明氦气模式下的动能歧视可有效去除95Mo测定过程中的多原子离子的干扰,氦气模式测定有效钼明显优于无气体模式;分别对待测溶液稀释5倍和未稀释的内标回收率趋势进行监测,发现未稀释的样品内标回收率随着测量样品数的增多呈下降趋势,而稀释5倍对基体干扰的消除有显著效果。对5个土壤样品分别重复测定6次,其RSD均小于4.1%;线性相关系数为1.0000;方法检出限为0.0012 mg/kg。综上,该方法测定土壤有效钼结果准确,重现性好,灵敏度高,且适合大批量样品的分析。     

火焰原子吸收法测定固氮酶活性中心模拟物中钼和铁含量的研究

本文报导了用空气-乙炔火焰原子吸收法,采用钼的灵敏线、铁的次灵敏线,在同一溶样中连续测定固氮酶活性中心模拟物中钼和铁含量的研究。     

火焰原子吸收法测定土壤中铜和铅

建立了逆王水-HClO4-HF分解法对土壤进行前处理,氘灯校正背景火焰原子吸收法分析土壤中铜和铅的方法。对逆王水-HClO4-HF分解法和王水-HClO4-HF两种分解土壤前处理方法和氖灯校正背景火焰原于吸收法和萃取火焰原子吸收法进行了比较。方法应用于土壤标准样品及样品的测定,获得了满意的结果。     

催化极谱法测定土壤中有效钼方法的改进

钼是植物必需的微量元素，参与植物体内氮元素循环，具有增强光合作用和提高植物抗旱、抗寒及抗病能力。采用钼-苯乙酸-氯酸盐-硫酸体系的极谱催化波测定土壤中有效钼，结果稳定且易于掌握，但当土壤中铁、锰含量较高时，干扰测定，用阳离子交换树脂分离，手续繁琐。本方法提出用氨水分     

一氧化二氮-乙炔火焰原子吸收法测定钢中钼

本文研究了测定钢中钼的一氧化二氮-乙炔火焰原子吸收法。考查了溶样用各种酸及钢中其它元素对钼测定的干扰,研究了防止或抑制干扰的方法。发现用Mo313.3毫微米作分析线时,钢中镍产生强烈正干扰。实验证实,这是镍吸收线313.4 毫微米的光谱干扰造成的。改用Mo317.0毫微米作分析线避免了镍的干扰。在绘制工作曲线的溶液及样品溶液中加入大量铝(1200微克/毫升)可消除其它元素的干扰。分析含钼标钢的结果表明,所建立的方法可用于钢中钼的日常分析。     

电感耦合等离子体质谱(ICP-MS)法测定云南富源耕地土壤中有效钼

有效钼是土壤质量评价不可缺少的指标,为准确高效测定土壤中的有效钼,样品采用Tamm溶液进行浸提,浸提液用硝酸(5%)稀释10倍,确定了分析元素钼的同位素⁹⁵Mo,¹⁰³Rh为内标,校正基体干扰和信号漂移,优化了仪器分析参数,利用电感耦合等离子体质谱仪(ICP-MS)碰撞模式(KED模式)进行有效钼的测定,建立的标准曲线相关系数为1.00,方法的检出限(3σ)为0.002μg/L,对3个国家一级标准物质样品进行土壤中有效钼含量的平行测定,相对误差小于2%,相对标准偏差(RSD)小于5%,对200余件实际样品进行不同方法外检比对,合格率为98%。方法具有操作简单、方便快捷,经济适用等特点,适合于各生产实验室各种类型土壤样品有效钼的大批量分析。     

石墨管原子吸收法测定原子簇化合物中钼铁含量

不久前,我们研究了火焰原子吸收测定Mo-Fe-S原子簇化合物中钼铁元素的方法,收到了较好的效果^[1]。但待测液中铁的含量小于20μg/ml时,铁对钼测定所产生的正干扰消除得不理想。并且当钼、铁浓度小于10μg/ml时,测量的准确度较差.为了克服以上不足,我们研究了石墨管原子吸收法测定低含量钼、铁元素的方法,取得了满意的结果.     

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.     

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.     

Atomic-absorption spectrophotometric determination of antimony, arsenic, bismuth, tellurium, thallium and vanadium in sewage sludge

Electrothermal atomic-absorption spectrophotometry (AAS), by use of a graphite furnace, in conjunction with sample pretreatment by homogenization, was evaluated as a rapid method for the determination of bismuth, thallium and vanadium in sewage sludge. This method was compared with use of flame, electrothermal and hydride-generation (for bismuth) AAS in conjunction with conventional acid digestion and dry-ashing pretreatments and was found to be applicable to this type of sample. Comparisons were also made between flame and hydride-generation AAS in conjunction with an acid digestion pretreatment for the determination of antimony, arsenic and tellurium in sewage sludge. The hydride-generation technique was considered the better for waste-water samples because of its greater sensitivity.     

Determination of tin in copper based alloys using a modified quartz atom-trap (STAT) and flame-atomic absorption spectrophotometry

Summary An improved system is reported for the determination of tin in copper-based alloys by flame-atomic absorption specved sensitivity and precision by factors of 2–3 compared to that obtained using conventional flame AAS. Determination of tin in a series of certified references samples demonstrates the improved precision of the proposed procedure.     

Periodic trends in sensitivity and its dependence on the properties of pyrolytic and non-pyrolytic graphite in graphite-furnace atomic-absorption spectrometry

The sensitivities for metal determination by GFAAS in the peak-height and integration modes were examined with pyrolytic graphite (PG) and non-pyrolytic graphite (NPG) tubes for 34 elements. It was found that there are periodic trends of the mole sensitivity and the elements can be classified according to whether their sensitivity of determination is enhanced by use of (a) the PG tube (alkali, alkaline-earth and transition metals); (b) the NPG tube (semi-metals); about equally by both tubes (Mg, Zn, Cd, and Pb). The mole sensitivity pM for atomic-absorption spectrometry (AAS) was defined as pM = -log(m(h)/A(w)) where m(h) is the weight of an element corresponding to 1% absorption and A(w) is the atomic weight. It was found that the pM values for graphite furnace AAS have a periodic trend similar to that for flame AAS and atomic-fluorescence spectrometry.     

在线螯合树脂富集火焰原子吸收光谱法测定天然水体中铜和锌

对螯合树脂富集——火焰原子吸收光谱法测定天然水体中痕量铜和锌的在线富集条件、干扰因素等进行研究,在线富集倍数达到两个数量级,在灵敏度与石墨炉原子吸收光谱法相当情况下,提高了测定准确度。     

Atomic-absorption spectrophotometric determination of tin by hydride generation in non-aqueous medium after extraction

Tin at the microgram level was extracted into chloroform with N-nitrosophenylhydroxamic acid (ammonium salt) from 0.5-1.5M hydrochloric acid medium. Tin hydride was generated from 1 ml of the chloroform extract mixed with 3 ml of 1% sulphuric acid solution in N,N-dimethylformamide. by injection of 3 ml of 2% sodium tetrahydroborate solution in N,N-dimethylformamide through the septum of the hydride generator. Tin was then determined by AAS at 224.6 nm with an acetylene-air flame, and nitrogen as carrier gas. The peak-height of the signal was linearly related to amount of tin up to 20 mug. The sensitivity of the determination was improved by the extraction. The method was applied to determination of tin in tinned foods and aluminium-base alloys with good accuracy and precision.     

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.     

探针-石墨炉原子吸收光谱法测定岩石矿物中的金

本文采用自制探针系统对探针-石墨炉原子吸收光谱法测金的性能,探针系统的制作,探针的处理,探针原子化法的检测限,灵敏度及抗干扰能力进行了详细的研究,探针原子化的各项指标均优于常规的管壁原子化法。采用本法可不必分离基体物质,直接测定地质样品中的金,所得结果与萃取原子吸收法的结果相吻合。     

Coupling of ultrasonic nebulization to flame furnace atomic absorption spectrometry—new possibilities for trace element determination

The use of ultrasonic nebulization (USN) with desolvation system for sample introduction in flame atomic absorption spectrometry (F AAS) and flame furnace atomic absorption spectrometry (FF AAS) with a nickel tube is described. Polytetrafluorethylene (PTFE) adaptors were built to replace the pneumatic nebulizer for USN-F AAS measurements. For USN-FF AAS analysis, an alumina injector allowed the direct introduction of the dry aerosol into the nickel tube. The analytical performance of both systems is shown for Ag, Bi, Cd, Cr, Cu, Mn, Pb, Sb, Se, Tl and Zn. The results demonstrate that a sensitivity gain of up to 39 times can be achieved using USN-FF AAS, mainly due to the increase in residence time and to the absence of dilution of the analyte by the flame gases, as the atomization takes place inside the nickel tube. However, elements that require higher atomization temperatures, such as Cr and Mn, are more efficiently determined using USN-F AAS. To evaluate the accuracy of the proposed methods for the determination of trace elements, five certified reference samples were analyzed, and good agreement was, in general, achieved between certified and determined values at a 95% confidence level. The relative standard deviation was frequently below 5%, demonstrating good precision, particularly for USN-FF AAS. In this sense, coupling of USN with F AAS and especially with FF AAS has proved to be simple, safe, with high precision and good accuracy, also maintaining some of the most important features of F AAS, such as the high analytical frequency and the low running cost.