Direct determination of traces of Ag, Cd, Pb, Bi, Cr, Mn, Co, Ni, Li, Be, Cu and Sb in environmental waters and geological materials by simultaneous multi-element graphite furnace atomic absorption spectrometry with Zeeman-effect background correction

A method was developed for direct determination of minor and trace amounts of Cr, Mn, Cu, Ni, Co, Li, Pb, Cd, Bi, Sb, Be and Ag in silicate rock, lake and stream sediments using a microwave oven dissolution method and a multi-element graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background correction device. The measurement technique was also suitable for direct determination of trace and ultra-trace amounts of these elements in drinking and seawater samples. A rock or sediment sample was brought into solution in a Teflon vessel by heating in a microwave oven with a mixture of hydrofluoric acid and aqua regia, followed by a further heating with a mixture of boric acid and ethylenediaminetetraacetic acid. The specified elements were directly determined in a group of four elements in one firing and eight elements in two firings from this solution or from a diluted solution using the optimum operating parameters developed in this work. The method, tested with 23 international reference rocks and sediments and seven international quality control and reference water samples, showed good to excellent agreement with the recommended values.     

王水消解-冷原子吸收光谱法测定土壤中汞

为了寻求一种更加适宜测定土壤中汞含量的测试方法,将检出限低、精密度高的冷原子吸收光谱法与便捷、高效的王水水浴消解土壤处理方式相结合,建立了王水消解-冷原子吸收光谱法测定土壤中汞。通过测定方法的线性相关性、方法检出限、准确度、精密度、加标回收率,并与原子荧光光谱法进行对比实验来评价该方法的有效性。王水消解-冷原子吸收光谱法在汞质量浓度0.0～1.0μg/L范围内线性良好,相关系数可以达到0.999 9,方法检出限为0.000 75mg/kg,土壤标准样品测试的相对标准偏差为4.0%～10.7%,实际样品加标回收率分别为93%～104%。采用原子荧光光谱法进行对比测试,原子荧光光谱法的方法检出限为0.002 5 mg/kg,相对标准偏差为4.8%～13.5%,加标回收率为104%～107%。结果表明,对于王水水浴消解土壤的方法不仅适用于原子荧光光谱法测定汞含量,同样可以应用于冷原子吸收光谱法中。所建立的王水消解-冷原子吸收光谱法具有更低的检出限,更优的准确度和精密度,有利于提高土壤样品测试的工作效率,值得推广。     

王水消解-冷原子吸收光谱法测定土壤中汞

为了寻求一种更加适宜测定土壤中汞含量的测试方法,将检出限低、精密度高的冷原子吸收光谱法与便捷、高效的王水水浴消解土壤处理方式相结合,建立了王水消解-冷原子吸收光谱法测定土壤中汞。通过测定方法的线性相关性、方法检出限、准确度、精密度、加标回收率,并与原子荧光光谱法进行对比实验来评价该方法的有效性。王水消解-冷原子吸收光谱法在汞质量浓度0.0~1.0μg/L范围内线性良好,相关系数可以达到0.9999,方法检出限为0.00075 mg/kg,土壤标准样品测试的相对标准偏差为4.0%~10.7%,实际样品加标回收率分别为93%~104%。采用原子荧光光谱法进行对比测试,原子荧光光谱法的方法检出限为0.0025 mg/kg,相对标准偏差为4.8%~13.5%,加标回收率为104%~107%。结果表明,对于王水水浴消解土壤的方法不仅适用于原子荧光光谱法测定汞含量,同样可以应用于冷原子吸收光谱法中。所建立的王水消解-冷原子吸收光谱法具有更低的检出限,更优的准确度和精密度,有利于提高土壤样品测试的工作效率,值得推广。     

Comparison of wet microwave digestion methods of plant materials for the determination of metals by flame atomic absorption spectrometry

Microwave closed-system wet digestion procedures for plant samples were examined. Each procedure was tested with samples of tobacco and cabbage, and included digestion by the use of different acids composition, almost complete evaporation of the digest, and then dissolution of the residue in 1% nitric acid. Three microwave digestion programs that varied power, duration, and temperature were used. Closed-vessel reactions followed open-vessel reaction-delay time. Using flame atomic absorption spectrometry on the digests, four or five elements were determined to evaluate effectiveness, precision and accuracy of analytes extraction into solution. After a preliminary study of tobacco digests, the four most effective procedures were chosen, and detailed investigations were carried out on both tobacco and cabbage reference materials. Although all four of the final procedures were accurate, the most precise procedure, with the lowest errors of determination, was using reverse ‘aqua regia’ for tobacco and ‘aqua regia’ for cabbage.     

原子荧光光谱法测定锡精矿中汞

建立了原子荧光光谱法测定锡精矿中汞的分析方法。试样经王水（1＋1）溶解,以盐酸（5%）为载流,氯化亚锡（200g/L）溶液为还原剂,用原子荧光光谱法测定样品中的汞。考察了测定的最佳条件、锡及共存元素对测定的影响。方法相对标准偏差为5.9%-6.3%,与冷原子吸收光谱法对比结果令人满意。方法的准确度和精密度均能满足分析需要,具有较强的实用性。     

Rapid determination of lead in steel by flameless atomic absorption spectrometry

A method for the determination of 1–100 p.p.m. of lead in high- and low-alloy steels by flameless atomic absorption is described. The sample was dissolved in aqua regia. and 2 μl of the diluted solution were pipetted into a Massmann-type furnace. Ashing of the sample at 625°C eliminated influences from hydrochloric acid. Fe, Cr and Ni gave similar negative interferences, which were compensated for by using low-alloy steel with standard additions. An interlaboratory comparison showed that this method gave the same result as extraction with TOPO in MIBK. The procedure could also be applied to commercial instruments. The time for a complete analysis including dissolution was 15 min.     

Rapid determination of antimony in steel by flameless atomic-absorption

A method for the determination of 1-30 ppm or more of Sb in steel by using flameless atomic absorption has been developed. The sample was dissolved in aqua regia and 10 mul were pipetted into the Massmann-type furnace. It was shown that interferences from HCl, HNO(3), Ni and Fe could be eliminated if oxygen was excluded and the heating rate was sufficiently high. Chromium was added to the samples and standards to compensate for its influence. Cu, Co, Mn, Ti and Sn did not interfere. An intercomparison with other laboratories showed that this method gives the same result as extraction with TOPO in MIBK. The time for a complete analysis including dissolution was 15 min.     

Quantitative Untersuchungen von Bauxiten Zentralgriechenlands mittels Atomabsorptionsspektroskopie und Flammenatomemission

Summary A rapid two-part procedure was described for the determination of the elements Al, Fe, Ti, Cr, Ni, V, Mn, Cu, Ag, Au, Ga, Si, Ca, Mg and K in bauxite samples from central Greece. After an NaOH decomposition and an HCl pressure decomposition as well as an aqua regia decomposition carried out in addition, an optimization of the measuring program in time was achieved by constant alternation of atomic absorption spectrometry and atomic flame emission. The elements Ga and Au were measured directly in their extracts using AAS.     

Simultaneous determination of trace metals in sewage and sewage effluents by inductively coupled argon plasma atomic emission spectrometry

Inductively coupled plasma excitation sources are adapted for the simultaneous determination of multiple elements in sewage and sewage effluents by atomic emission detection. Digestion with aqua regia in test tubes is recommended for sample preparation. A typical comparison of lead in sewage by atomic emission (x) and atomic absorption (y) gave a least-squares fit of x = 0.98 y + 0.03 with a standard error of 0.5 mg l^-1 and a correlation coefficient of 0.996. More complete comparison data by the atomic emission and absorption techniques are presented for other elements.     

水浴加热密闭溶样石墨炉原子吸收光谱法测定化探样品中的痕量金

以王水、氟化钾、Fe3+溶液为溶剂,对化探样品进行水浴加热分解1.5 h,经泡沫塑料吸附后,于90℃以上硫脲溶液中解吸20 min,然后采用石墨炉原子吸收光谱仪测定其中的金含量。对仪器分析条件进行了优化。金的质量分数在0.1~100.0 ng/g范围内与吸光度呈良好的线性,线性相关系数r2=0.999 3,检出限为0.100 ng/g。该方法对金标准物质测定结果的相对标准偏差为5.96%~9.25%(n=12),对国家一级标准物质进行分析,测定结果与标准值相符合。该方法满足1∶50 000化探样品中痕量金的分析要求。     

Determination of platinum and palladium in environmental samples by graphite furnace atomic absorption spectrometry after separation on dithizone sorbent

A graphite furnace atomic absorption method of platinum and palladium determination after their separation from environmental samples has been presented. The samples were digested by aqua regia and the analyte elements were separated on the dithizone sorbent. The procedure of sorbent preparation was described and their properties were established. Two various procedures of elution by thiourea and concentrated nitric acid were described and discussed. The low limit of detection was established as 1 ng g⁻¹ for platinum and 0.2 ng g⁻¹ for palladium.There was also investigated the behaviour of platinum and palladium introduced into the soil in various chemical forms.     

Trace elements in soil: Their determination and speciation

Summary The different types of soil analysis are reviewed in-outline and some recent developments and methodologies are discussed.For the determination of the total trace element content of soils, conventional, multi-element, solid sample methods including d.c. arc optical emission and spark source mass spectrometric procedures are briefly considered together with the potential of current X-ray fluorescence, solid sample graphite furnace atomic absorption and glow discharge mass spectrometry.The use of strong acid digestion, with for example aqua regia, for the determination of pseudo-total concentrations of heavy or toxic metal accumulations in soil is described.The limitations of solution methods for multi-element analysis of soils are outlined together with the prospects for the use of soil slurries to eliminate the sample preparation and dilution problems associated with the dissolution of soils. The difficulties in taking reproducible and representative samples of inhomogeneous materials such as soils are highlighted.Trace element speciation can be defined as the identification and quantification of the different forms or phases in which they occur in soils. Some examples of such procedures and extractants for both essential and toxic elements in soils are presented. The difficulties of trace element speciation in soils as distinct from soil extracts or soil solutions are illustrated briefly.     

双孔石墨管原子吸收法测定化探样品中的痕量金

建立了双孔石墨管原子吸收法测定化探样品中痕量金的方法。以王水溶解样品,泡沫塑料吸附,10 g/L的硫脲溶液解脱,2%抗坏血酸作为基体改进剂,用双孔石墨管原子吸收法测定化探样品中的痕量金。该方法仪器分析时间由65 s缩短到32 s,提高了工作效率,方法标准曲线线性相关系数为0.999 8,检出限为0.045 ng/g,测定结果的相对标准偏差为4.1%~6.9%(n=7),标准样品测定值与推荐值的相对偏差小于3.24%。该法适合批量化探样品中金的测定。     

水为载流-原子荧光光谱法同时测定土壤中痕量砷、汞

改变原子荧光光谱法以稀酸为载流的进样方式,以水为载流在新型双道原子荧光光谱仪上同时测定了土壤中的痕量砷(As)、汞(Hg)。方法采用王水水浴加热溶解样品,用50 g/L硫脲-抗坏血酸混合溶液预先将砷还原为+3价,保持10%(体积分数)以上盐酸浓度,不转移直接定容静置后测定。优化了仪器工作条件,详细考察了以水为载流测定的可行性,选择了同时测定As、Hg所需的硼氢化钾浓度和盐酸浓度。方法节省了酸试剂用量,操作快速,单个样品测定仅需20s左右。方法检出限As为0.005 mg/kg,Hg为0.0008 mg/kg,相对标准偏差(RSD%,n=7)在1.0%～7.4%,经土壤国家标准物质和实际样品验证,适合土壤中痕量As、Hg的同时快速测定。     

水载流-原子荧光光谱法同时测定土壤中痕量砷、汞

改变原子荧光光谱法以稀酸为载流的进样方式,以水为载流在新型双道原子荧光光谱仪上同时测定了土壤中的痕量砷(As)、汞(Hg).采用王水水浴加热溶解样品,用50 g/L硫脲-抗坏血酸混合溶液预先将砷还原为As(Ⅲ),保持10％(体积分数)以上盐酸浓度,不转移直接定容静置后测定.优化了仪器工作条件,详细考察了以水为载流测定的...     

Determination of traces of gold by hollow-cathode emission

The utility of a commercially available demountable hollow-cathode tube for emission spectrometric trace element analysis of solutions is demonstrated. The effects of cathode material, clean-up procedure, filler gas, and tube current were investigated to determine the conditions resulting in a satisfactory compromise between sensitivity and stability. Solutions of gold as myochrysine and as the metal dissolved in aqua regia were analyzed to show application of the commercial tube.     

Comparative study of optimised BCR sequential extraction scheme and acid leaching of elements in the certified reference material NIST 2711

The optimised BCR sequential extraction procedure and a 4 h 1 mol L⁻¹ HCl partial extraction have been performed on the NIST 2711 reference material for a suite of 12 elements (Cd, Sb, Pb, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As) using magnetic sector ICP-MS. A pseudo-total aqua regia digest of NIST 2711 has also been undertaken for quality assurance purposes, and comparison of the sum of the four BCR fractions, which included an aqua regia digest on the residue, with the pseudo-total aqua regia digest has been used to assess the accuracy of the BCR partitioning approach. As a result of this work, discrepancies between previous studies about BCR partitioning of elements in NIST 2711 have been discussed and an increase in confidence about the use of BCR partitioning scheme on seven elements (Cd, Pb, Al, Mn, Fe, Cu, Zn) in this standard material has been obtained. On the other hand, BCR partitioning for Sb, Cr, Co, Ni and As has been provided for the first time. Partial extraction results are also reported for the same 12 elements analysed by the optimised BCR procedure, with the partial extraction results exhibiting a strong correlation with the sum of the three labile steps of the BCR procedure.     

Determination of palladium(II) with picramine-epsilon

We found a reaction of palladium(II) with picramine-epsilon to give a colored complex with an absorption maximum at 556 nm and a molar absorption coefficient of (2.01 ± 0.02) × 10⁴. Conditions of spectrophotometric reaction were selected for determining palladium(II) in nitric acid solutions or solutions containing aqua regia without the conversion of initial complexes into other forms. A rapid procedure was developed for the direct spectrophotometric determination of palladium(II) in concentrations down to 0.5 mg/L in various process solutions (including those containing nitric acid and aqua regia) within 15 min.     

Determination of noble metals in silicate rocks, ores and metallurgical samples by simultaneous multi-element graphite furnace atomic absorption spectrometry with Zeeman background correction

A new method has been developed for rapid determination of mug/g and ng/g amounts of noble metals in silicate rocks, ores and metallurgical samples by attacking with hydrofluoric acid and aqua regia, preconcentration by ion-exchange chromatography and measuring in a simultaneous multi-element graphite furnace atomic absorption spectrometer equipped with a polarized Zeeman background correction device which eliminated interferences from any incompletely separated common elements. The method was tested for Ru, Rh, Pt, Ir, Pd, Ag and Au with three Canadian certified reference materials, and then applied to the determination of ng/g amounts of these elements in four new Canadian candidate reference materials.     

Performance of permanent iridium modifier in the presence of corrosive matrix in graphite furnace atomic absorption spectrometry

The influence of up to 16% HNO3, 28% HCl, and the mixture of both acids in aqua regia on the analytical performance of electrodeposited modifiers (Ir or Ir+Pd) was evaluated and discussed. Cadmium was used as an example of volatile elements often determined by graphite furnace atomic absorption spectrometry (GF AAS). In the presence of HCl, the maximum pyrolysis temperature that could be applied was found to be 600 degrees C. In the presence of HNO3 and aqua regia, both modifiers stabilized cadmium up to 800 degrees C. The long-term performance of electrodeposited Ir or Ir+Pd was not influenced by mineral acids; moreover the tube lifetime was significantly prolonged compared with a non-modified tube.