Direct Analysis of Coffee and Tea for Aluminium Determinationby Electrothermal Atomic Absorption Spectrometry

 A method for direct analysis of tea and coffee samples by using electrothermal atomic absorption spectrometry is described. Coffee and tea from different sources were analyzed without digestion step. For slurry analyses the samples were ground, sieved at 105 μm and then suspended in 0.2% v/v HNO₃ and 10% v/v Triton X-100 medium. For liquid phase aluminium determination the samples were prepared in the same way and only the liquid is introduced directly into the graphite furnace. Calibration was performed by aqueous standards for both cases and the determinations were carried out in the linear range between 50 and 250 μg L⁻¹. The characteristic mass of aluminium and the detection limit were 45 pg and 2 μg L⁻¹, respectively. Using a typical 0.1% m/v coffee slurry sample, the relative standard deviation of measurements (n=15) for repeatability was about 8.2%. Received December 27, 1998. Revision March 18, 1999.     

Determination of Bismuth in Sediment and Soil by Ultrasonic Slurry Sampling Electrothermal Atomic Absorption Spectrometry

The analytical conditions of the direct determination of bismuth in some certified reference material samples (soil and sediment) by slurry sampling Zeeman electrothermal atomic absorption spectrometry (ETAAS) with the use of automated ultrasonic slurry mixing are discussed. Palladium nitrate was used as a chemical modifier. With the use of this modifier it was possible to stabilize bismuth to the pyrolysis temperature of 1300 °C. Platform atomization was performed at 2050 °C. The results of determination are calculated from a simple, aqueous standards based calibration graph. Statistical evaluation of the results indicate that the slurry sampling method is reproducible and the accuracy of the proposed method is very good. This method is rather simple and its other advantages are good sensitivity and relatively short analysis time.     

Determination of Antimony in Sediments by Zeeman-Corrected Electrothermal Atomic Absorption Spectrometry with Ultrasonic Slurry Sampling

A method was developed for the determination of antimony in slurried sediments (on the basis of samples of three Certified Reference Materials) by electrothermal atomic absorption spectrometry (ETAAS) with Zeeman-effect background correction. Slurried samples were prepared in 6% nitric acid containing 0.02% of Triton X-100. A mixed palladium/magnesium chemical matrix modifier, L'vov platform atomization and a temperature-time program with a relatively short (10 s) sample pyrolysis stage were used. The results of the determinations by this technique are in very close agreement with certified values and the repeatability of this analytical procedure expressed in terms of relative standard deviation was typically better than 9% at the slurry concentration of approx. 90 mg/2 mL. The characteristic mass of Sb (at the spectral line 231.1 nm) was 25.6 pg and the limit of detection (calculated for 100 mg/2 mL slurry) was about 0. 04 μg/g.     

Sensitive Method for Trace Determination of Mercury in Wines Using Electrothermal Atomic Absorption Spectrometry

An accurate, simple and precise method for total mercury determination in wines is described. Liquid/liquid extraction of inorganic and organic mercury species directly from untreated wine samples is recommended as a preconcentration procedure prior to determination by electrothermal atomic absorption spectrometry (ETAAS). Ammonium pyrrolidinedithiocarbamate was used as complexation agent. The optimal instrumental parameters for ETAAS measurement of mercury species extracted are proposed. The detection limit for total mercury determination is 0.2µgL^–1. The relative standard deviation is 15–22% for mercury in wine in the range of 0.2–5µgL^–1. The proposed procedure has been successfully applied to the determination of mercury in bottled wines in Bulgaria and Macedonia.     

Heated Slurry Sampling for the Determination of Cadmium in Food by Electrothermal Atomic Absorption Spectrometry

A heating procedure is reported with slurry sampling electrothermal atomic absorption spectrometry to improve the accuracy of cadmium determination in food. In comparison to conventional slurry sampling, the heating significantly increased cadmium recovery and improved the precision. For the optimized procedure, 25–250 mg of food were treated with 2% HNO₃ and 1% H₂O₂ with heating at 120°C for 20 min, followed by the addition of 50 µL of 10% Triton X-100, and homogenization in an ultrasonic bath prior to analysis. Tungsten and rhodium were employed as a permanent modifier with optimum pyrolysis and atomization temperatures of 500°C and 1500°C. Calibration with aqueous standards resulted in good agreement between certified or information values and measured results at the 95% confidence level. A characteristic mass of 0.8 ± 0.1 pg and a detection limit of 0.7 ng g^?1 for a 2% slurry were obtained. The method was employed for the direct determination of cadmium in food certified reference materials.     

Simple Method for Determination of Lead in Hair Dyes Using Slurry Sampling Graphite Furnace Atomic Absorption Spectrometry

A fast, simple and sensitive method for determining of lead in hair dyes using graphite furnace atomic absorption spectrometry with slurry sampling was developed. Multivariate optimization was used to establish optimal analytical parameters through a fractional factorial and a central composite design. The samples were submitted for direct analysis without prior digestion and were diluted in 2.5% v/v HNO₃ and 1.5% v/v H₂O₂. Palladium (chemical modifier) and rhodium (permanent modifier) were selected from several potential modifiers. The optimal conditions were a pyrolysis time of 10 s (liquid and dust dyes) 20 s (cream dyes), a pyrolysis temperature of 789°C (liquid dyes) or 750°C (cream and dust dyes) and an atomization temperature of 1800°C for all dyes. Under optimum conditions, the calibration graph is linear in the 1.50–50.0 µg L^?1 concentration range, with a detection limit of 0.33, 0.44, and 0.39 µg L^?1 for liquid, dust, and cream hair dyes, respectively. The relative standard deviation ranged from 1.63 to 4.56%. The recovery rate ranged from 85 to 108%, and no significant differences were found between the results obtained with the proposed method and the microwave decomposition analysis method of real samples. The concentration ranges obtained for lead in the hair dyes samples were 1.00–11.3 µg L^?1 for liquid dyes, 14.0–100 µg kg^?1 for dust dyes, and 19.9–187 µg kg^?1 for cream dyes.     

悬浮体制样石墨炉原子吸收光谱法直接测定食品中的Cu、Zn、Mn

本文提出以PTFE作为化学改进剂，悬浮体制石墨炉原子吸收光谱法（GFAAS）测定食品中痕量Cu、Zn、Mn的新方法，对GFAAS测定Cu、Zn、Mn的条件进行了优化。在选定的实验条件下，测定Cu、Zn、Mn的特征捏分别为3．1pg,0.8pg和1．8pg。采用水溶液工作曲线法直接分析了食品试样中的痕量Cu、Zn、Mn，其测定结果参考值相一致，本方法无需任何化学前处理，灵敏，简便，快速。     

Determination of Iron in Layered Crystal Sodium Disilicate and Sodium Silicate by Flame Atomic Absorption Spectrometry with Boric Acid as a Matrix Modifier

As a novel type builder for phosphate-free detergent1,2, layered crystal sodium disilicate has many advantages over other builders for phosphate detergents. The raw material of layered crystal sodium disilicate is sodium silicate. Because of the effects o…     

火焰原子吸收分光光度法测定五氧化二钒中铁及氧化钾、氧化钠含量

五氧化二钒样品用盐酸分解,在稀盐酸介质中,用原子吸收分光光度计分别于248.3,766.5,589.0 nm波长处,使用空气–乙炔火焰,测量五氧化二钒中铁及氧化钾、氧化钠含量。在最佳实验条件下,铁、氧化钾、氧化钠的质量浓度分别在0.05~0.20,0.05~0.80,0.20~1.0 mg/L范围内与吸光度线性关系良好,相关系数分别为0.998 6,0.994 3,0.994 2。方法检出限铁为6.7μg/L,氧化钾为1.0μg/L,氧化钠为1.4μg/L,加标回收率为95.9%~103.0%。铁、氧化钾、氧化钠测定结果的相对标准偏差分别为3.2%,4.2%,2.9%(n=6)。该方法适合五氧化二钒中铁及氧化钾、氧化钠的测定。     

Determination of Lead, Chromium, Manganese and Zinc in Slurries of Botanical and Biological Samples by Electrothermal Atomic Absorption Spectrometry Using Tungsten-Containing Chemical Modifiers

Lead, Cr, Mn and Zn in slurries of botanic and biological samples were determined by electrothermal atomic absorption spectrometry (ETAAS) using W, Ir, NH₄H₂PO₄, W and NH₄H₂PO₄, Ir and NH₄H₂PO₄, W and Ir, and W + Ir + NH₄H₂PO₄ chemical modifiers in an 0.2% (v/v) Triton X-100 plus 0.2% (v/v) nitric acid mixture. Zeeman effect background correction was performed and platforms inserted into graphite tubes were used. Comprehensive comparative studies were carried out with respect to pyrolysis and atomization temperatures, atomization and background absorption profiles, characteristic masses, detection limits and accuracy of the determinations in the presence and absence of modifiers. The mixture of W + Ir + NH₄H₂PO₄ was found to be preferable for the determination of Pb, Cr, Mn and Zn in slurry samples. The pyrolysis temperatures of the analytes were increased up to 1250 °C for Pb, 1000 °C for Zn, 1400 °C for Cr and Mn by using W + Ir + NH₄H₂PO₄ with an 0.2% (v/v) Triton X-100 plus 0.2% (v/v) nitric acid mixture used as diluent solution. The optimum masses of the mixed modifier components were found to be 20 µg W + 4 µg Ir + 50 µg NH₄H₂PO₄. The characteristic masses of Pb, Cr, Mn and Zn obtained are 16.3, 5.6, 0.1 and 1.1 pg, respectively. The detection limits of Pb, Cr, Mn and Zn based on integrated absorbance for 0.5% (m v⁻¹) slurries were found to be 0.14, 0.06, 0.02 and 0.01 µg g⁻¹, respectively. The slurries of botanic and biological certified and standard reference materials were analyzed with and without the modifiers. Depending on the sample type, the percent recoveries increased from 63 up to 104% for analytes when using the proposed modifier mixture.     

Study on Slurry Sampling Technique for the Determination of Trace Metals in Food by Electrothermal Atomic Absorption Spectrometry

The slurry sample introduction approach is a convenient method of solid sampling that allows the rapid and accurate determination of trace metals in foodstuffs by ETAAS. Since complex dissolution of the samples is avoided,sample handling is minimal and possible sources of contamination are reduced. Among which, preparation of suspension and optimization of the graphite furnace heating program are important. First, the samples are pulverized using homogenizer at speed lOOOOr/min. Ninety percent of the particles are less than 30um in diameter after a pulverizing period of 6min for vegetable, fruit and liver; 25min for beef and pork; 8min for cereals, which allow the preparation of stable slurries up to at least 10%. Second, suspensions are prepared in medium containing 0.15% agar as stabilizing agent, which stabilizing time is up to two days.     

悬浮体制样/氟化电热蒸发-电感耦合等离子体原子发射光谱直接测定粉煤标样中的微量钒和钛

本文提出了悬浮体制样氟化ETV-ICP-AES直接测定粉煤中微量钒和钛的新方法。采用聚四氟乙烯为氟化剂;促进V、Ti的蒸发,检出限分别为1.5和0.8ng/ml,RSD分别为2.8％和1.9％,线性范围达三个数量级,该法用于NIST SRM 1635粉煤标样中V和Ti的测定,结果与参考值吻合很好。     

Direct Determination of Arsenic in Beet Sugar Molasses Using Nickel as Chemical Modifier by Electrothermal Atomic Absorption Spectrommetry

A simple electrothermal atomic absorption spectrometric (ETAAS) method is described for direct determination of arsenic in sugar beet molasses samples. Pyrolytic graphite tubes were used as atomizers. The compression between modifiers such as nickel nitrate, palladium nitrate and the mixture of palladium and magnesium nitrate were performed and nickel nitrate selected as the best chemical modifier. The effects of pyrolysis and atomization temperature were also studied and the pyrolysis temperature of 900 °C and atomization temperature of 2300 °C have been chosen for temperature program. The detection limit of the method was 1 ng/mL As in sugar beet molasses samples. The relative standard deviation for ten determination of a spiked sample with concentration of 50 ng/mL As was 2.4%. The accuracy of the method was confirmed by the analysis of spiked samples. The linear rang of calibration is in the range of 1‐100 ng/mL of arsenic.     

火焰原子吸收法快速测定铁矿石中金属铁

探讨了火焰原子吸收法(FAAS法)快速测定铁矿石中金属铁的分析条件。对试样的溶解方法、元素分析线、共存元素干扰、仪器分析最佳条件等进行了试验。金属铁含量在0.2%~2.0%范围与吸光度呈良好的线性,线性方程为y=22.924x–0.8458,相关系数r=0.9991。将该法用于铁精粉样品中金属铁的测定,测定结果的相对标准偏差为1.10%~2.98%(n=6),加标回收率为98.0%~103.0%。     

火焰原子吸收光谱法测定蘑菇中钾、钠和铷

1 引言 蘑菇是生活中常见食品,含有大量的无机元素和有机成分。钾、钠、铷是人体所必需的常量元素,有着重要的生理作用。目前,国内对蘑菇中钾、钠、铷的测定尚未见报道。本文采用火焰原子吸收光谱法测定了蘑菇中的钾、钠、铷,得到了满意的结果。2 实验部分     

黄钠铁矾中铁的测定

准确快速测定黄钠铁矾中铁的含量有利于控制铁湿法冶金的流程。采用氢氧化钠溶液分解试样,盐酸(1+9)溶解滤渣,蒸发除过量酸,氨水沉淀分离铜、镍、钴等元素,再用稀盐酸溶解沉淀。在盐酸介质中,SnCl_2将大部分Fe(Ⅲ)还原为Fe(Ⅱ),钨酸钠为指示剂,用TiCl_3还原呈钨蓝色,重铬酸钾滴定至蓝色褪去。再以二苯胺磺酸钠为指示剂,重铬酸钾标准溶液滴定测定样品中铁的含量。实验表明,黄钠铁矾中共存干扰元素绝大部分被分离,同时与酸溶解法进行比较,测定数据一致,相对标准偏差(n=9)小于0.1%。     

A Simple and Fast Method for Manganese Determination in Antihypertensive Drugs by Slurry Sampling Graphite Furnace Atomic Absorption Spectrometry

Abstract

A simple and rapid procedure for the determination of manganese in anti‐hypertensive drugs is proposed. The samples were treated with dilute nitric acid (1.2% v/v) with stirring using a vortex stirrer to yield a slurry. To determine the best conditions for analysis by graphite furnace atomic absorption spectrometry (GF AAS), a planning factorial was initially employed that demonstrated that the non‐use of chemical modifiers and the use of lower pyrolysis temperatures were more appropriate. Next, the pyrolysis and atomization temperature curves were obtained. The best pyrolysis and atomization temperatures encountered were 500 and 2200°C, respectively. Calibration was performed by matrix matching. The characteristic mass was 0.70±0.14 pg (the recommended mass was 0.60 pg); the limits of detection and quantification were 0.23 and 0.77 µg l^?1, respectively. The precision obtained in the intra‐ and inter‐assay studies of the drug spiked with 0.5, 1.0 and 1.5 µg l^?1 of Mn did not exceed 11% (n=7). Recovery studies of the drug spiked with three levels (n=7) of Mn yielded results between 101.0±4.5 and 116.3±9.7%. The results of an analysis of a certified urine sample (two levels of Mn) agreed at a 95% level of confidence. Forty‐eight antihypertensive drug samples were analyzed, and the results varied from 2.9 ng to 1.9 µg of Mn per capsule^?1.     

Flame Atomic Absorption Spectrometric Determination of Gold and Palladium Using Microcolumn On-line Preconcentration and Separation

A microcolumn on-line preconcentration and separation system was developed for the flame atomic absorption spectrometric (FAAS) determination of trace levels of gold and palladium. The analytes were selectively adsorbed onto the microcolumn packed with 2-mercaptothiazole immobilized silica gel (MBTSG) in an acidity range of 0.1 to 6.0M HCl at a sampling flow rate of 4.0mLmin^–1. The analytes adsorbed could be desorbed by a thiourea solution with a flow rate of 2.0mLmin^–1. Most of the common coexisting metal ions at a concentration of 25.0mgmL^–1 and anions at a concentration of 50.0mgmL^–1 did not interfere with the preconcentration and determination of Au and Pd. The limits of detection (LOD), defined as three times the standard deviation of the blank (3), of Au and Pd are 10ngmL^–1 and 26ngmL^–1, respectively, with a preconcentration time of 60s. The relative standard deviation (RSD) is about 2.0% for 0.20µgmL^–1 Au and 0.30µgmL^–1 Pd. With a sample loading time of 30min, 6.7ngmL^–1 Au and 10ngmL^–1 Pd can be preconcentrated quantitatively. A geological sample, an anode slime and a secondary nickel alloy were successfully determined with the proposed method, and the results obtained showed good agreement with the certified values.Received December 23, 2002; accepted May 14, 2003 Published online August 8, 2003