Trace Determination of Manganese in Urine by Graphite Furnace Atomic Absorption Spectrometry and Inductively Coupled Plasma–Mass Spectrometry

This paper describes a simple and sensitive method for the determination of manganese in human urine by graphite furnace atomic absorption spectroscopy (GFAAS), which includes sample preparation by microwave digestion. Matrix modifier combinations, the digestion power, pyrolysis, and atomization temperatures were optimized. A mixture of 5.0 µg Pd(NO₃)₂ and 3.2 µg Mg(NO₃)₂ modifier presented the best performance. The optimal temperatures for pyrolysis and atomization were 1500°C and 1950°C, respectively. The GFAAS method was compared to inductively coupled plasma–mass spectrometry (ICP–MS) for the determination of manganese in urine. Analytical figures of merit for GFAAS and ICP–MS were: accuracy (3.46%, 2.19%), precision (3.61%, 5.84%), LOD (0.109 µg · L^?1, 0.015 µg · L^?1), LOQ (0.327 µg · L^?1, 0.045 µg · L^?1), and recovery (80–100%, 74–89%). Both methods were employed for the determination of Mn in urine and the results were compared statistically.     

Application of Solid Sampling for the Determination of Total Fluorine in Fish and Seafood by High-Resolution Continuum Source Graphite Furnace Molecular Absorption Spectrometry

Total fluorine concentrations in some fish species and seafood such as mussels, squid (calamary), and shrimp were determined using the molecular absorption of calcium monofluoride (CaF) generated in a graphite furnace using a high-resolution continuum source atomic absorption spectrometer and direct solid sampling. The fish fillets and seafood were dried at 110°C, minced finely, put on the platform using masses less than 1.2?mg, and introduced to the graphite furnace with 20?µg of calcium by a solid sampling accessory. The effects of CaF wavelength, graphite furnace program, amount of sample introduced to the furnace, the use of modifier on the determination of fluorine were investigated and optimized. The absolute limit of detection and characteristic mass of the method were 0.28 and 0.14?ng of fluorine, respectively. By applying the optimized parameters, the concentrations of fluorine in various fish species and seafood were determined.     

石墨炉原子吸收法测定生物样品中的铊

为建立测定生物样品中铊的石墨炉原子吸收法,通过微波消解,采用基本改进剂,改变石墨炉灰化温度等操作条件,提高了该法的准确度和精密度.结果表明,方法的线性范围为0～100 μg/L;检出限:血为0.10 mg/L;尿为0.02 mg/L;头发为0.20 mg/kg;回收率:血为83.1%～108%;尿为89.6%～105%...     

Determination of lead in hair and its segmental analysis by solid sampling electrothermal atomic absorption spectrometry

A rapid and practical solid sampling electrothermal atomic absorption spectrometric method was described for the determination of lead in scalp hair. Hair samples were washed once with acetone; thrice with distilled-deionized water and again once with acetone and dried at 75 °C. Typically 0.05 to 1.0 mg of dried samples were inserted on the platforms of solid sampling autosampler. The effects of pyrolysis temperature, atomization temperature, the amount of sample as well as addition of a modifier (Pd/Mg) and/or auxiliary digesting agents (hydrogen peroxide and nitric acid) and/or a surfactant (Triton X-100) on the recovery of lead were investigated. Hair samples were washed once with acetone; thrice with distilled-deionized water and again once with acetone and dried at 75 °C. Typically 0.05 to 1.0 mg of dried samples were inserted on the platforms of solid sampling autosampler. The limit of detection for lead (3σ, N = 10) was 0.3 ng/g The addition of modifier, acids, oxidant and surfactant hardly improved the results. Due to the risk of contamination and relatively high blank values, the lead in hair were determined directly without adding any reagent(s). Finally, the method was applied for the segmental determination of lead concentrations in hair of different persons which is important to know when and how much a person was exposed to the analyte. For this purpose, 0.5 cm of pieces were cut along the one or a few close strands and analyzed by solid sampling.     

Application of Solid Sampling Device for Direct Determination of Chromium and Nickel in Lubricating Oils by Graphite Furnace Atomic Absorption Spectrometry

Abstract

One method using a solid sampling device for the direct determination of Cr and Ni in fresh and used lubricating oils by graphite furnace atomic absorption spectrometry are proposed. The high organic content in the samples was minimized using a digestion step at 400°C in combination with an oxidant mixture 1.0% (v v^?1) HNO₃ + 15% (v v^?1) H₂O₂ + 0.1% (m v^?1) Triton X-100 for the in situ digestion. The 3-field mode Zeeman-effect allowed the spectrometer calibration up to 5 ng of Cr and Ni. The quantification limits were 0.86 µg g^?1 for Cr and 0.82 µg g^?1 for Ni, respectively. The analysis of reference materials showed no statistically significant difference between the recommended values and those obtained by the proposed methods.     

Determination of Lead in Lipstick by Direct Solid Sampling High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry: Comparison of Two Digestion Methods

A new analytical procedure for the determination of lead in lipstick has been developed using direct solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry (SS HR CS GFAAS). The performance of this method has been compared to acid digestion methods for sample preparation, with or without hydrofluoric acid (HF) with inductively coupled plasma mass spectrometry (ICP-MS) detection. Good reliability was obtained for all three methods; the results obtained for certified reference materials with concentrations between 1 and 20 ppm were in agreement with the certified values. However, for materials with complex matrices, such as pearl or Ca-Na borosilicate, only ICP-MS with HF sample digestion or AAS with direct solid sampling allowed complete recovery of lead. To avoid the use of hazardous acids, the development of SS HR CS GFAAS is an interesting alternative. With the AAS method, a characteristic mass of 13.2 pg of lead was obtained, and the limit of detection was 0.005 µg/g. The performance of the method was evaluated by determining lead in lipstick. The use of the solid sampling technique constitutes a good alternative for accurate and rapid determination of lead content in lipstick and cosmetic raw materials, with a suitable limit of detection and a reduced risk of contamination or of analyte loss. Another alternative would be to use ICP-MS determination in conjunction with microwave-assisted acid digestion without the use of HF, which implies accepting a quantification of “nearly total” lead, closer to a “bio-extractible” fraction.     

Preconcentration of ultra-trace copper in water samples with nanometer-size TiO2 colloid and determination by GFAAS with slurry sampling

A method is presented for the preconcentration of Cu(II) ions using a nanometer-sized TiO₂ colloid, and for their determination in environmental water using graphite furnace atomic adsorption spectrometry (GFAAS) with slurry sampling. The adsorption efficiency is above 97% and is reached within short time at pH values between 5.5 and 6.0. Cu(II) was determined by GFAAS without elution. Conditions such as colloid dosage and effects of other ions were studied. The detection limit (3 σ) and the relative standard deviation are 290 ng L^-1 and 9.8% (n?=?6), respectively. This simple and rapid method was successfully applied to spiked environmental samples with recoveries ranging from 97% – 104%.     

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.     

微波消解石墨炉原子吸收法测定人发中的铅、镉

采用石墨炉原子吸收分光光度法(GFAAS)测定人发中的铅、镉含量.采用微波消解法消解样品,加入(NH4)2SO4+KH2PO4基体改进剂消除干扰,对消化剂种类、消解压力、仪器条件等进行了探索.方法简便、准确度高,Pb和Cd的平均回收率分别为101.8%和107.1%,相对标准偏差(RSD)为5.14%和6.80%,方法检出限Pb为9.53 ng/mL,Cd为0.78 ng/mL.     

Determination of erbium and neodymium dopants in bismuth tellurite optical crystals by graphite furnace atomic spectrometry techniques

Application of concentrated HCl as a solvent and triammonium citrate (TAC) as a chemical modifier is advantageous for the determination of Er and Nd dopants in bismuth tellurite (Bi₂TeO₅) single crystals by graphite furnace atomic absorption spectrometry (GFAAS). The use of mini-flow of the internal gas, instead of gas stop, results in better precision at a price of a relatively small decrease in sensitivity. By evaluating integrated absorbance (A_int) signals for the GFAAS measurements (in the presence of matrix and TAC additive), characteristic mass values of 42 and 320 pg, and a limit of detection (LOD) of 4.9 and 131 μg l⁻¹ are found for Er and Nd, respectively. These LOD data correspond to 0.78 μg g⁻¹ Er and 21 μg g⁻¹ Nd in the solid samples. The calibration curves are linear up to 0.33 and 2.9 mg l⁻¹ concentrations in the solutions of Er and Nd, respectively. The ratio of the A_int signals of Er and Nd under gas stop and mini-flow were found near constant (1.34) with and without the matrix plus TAC. According to the vaporisation studies by graphite furnace electrothermal vaporisation inductively coupled plasma atomic emission spectrometry (GF-ETV-ICP-AES), the vaporisation of Bi and Te components of the solid Bi₂TeO₅ can be completed at 1200°C in a relatively short time, ensuring a preconcentration for the Er and Nd dopants, which do not vaporise below 2200°C in an argon atmosphere. On the other hand, fast vaporisation can be performed for the analytes at 2200°C with the use of CCl₄ vapour (∼0.5 v/v%) in the internal furnace gas (Ar). It was estimated for the Er analyte that by applying 10 mg of solid sample in the GF-ETV device (dispensed into a graphite sample boat) and using a two-step heating procedure (prevaporisation of the matrix in argon and vaporisation of the analyte in a chlorinating atmosphere), the lower limit of the quantitative determination with the ICP-AES method would be approximately one order of magnitude better than attainable with the GFAAS method based on dissolution.     

Atomic absorption spectrometric screening and gas chromatographic-mass spectrometric determination of organotin compounds in marine mussels: an application in samples from the Venetian Lagoon

A new analytical approach for the determination of organotin compounds (OTC) in mussel samples has been developed and evaluated. A preliminary step, performed by graphite furnace atomic absorption spectrometry (GFAAS) for the total tin determination may be followed by gas chromatographic-mass spectrometric (GC/ MS) speciation only for the characterization of those samples exhibiting total tin concentration higher than 30 ng/g wet weight (GFAAS limit of detection). The GFAAS method was optimized using Pd nitrate under reducing conditions as matrix modifier to minimize NaCl interferences. Organotins were derivatized with a Grignard reagent for GC/MS analysis (TBT limit of detection = 80 ng/g). An application of this strategy was performed on mussel samples collected from the Venetian Lagoon.     

Feststoffanalytik mit Autoprobe-GFAAS

Summary A new graphite system has been developed for GFAAS combining the autoprobe technique and solid sampling analysis. Based on previous studies with D₂-background corrected solid sampling GFAAS it has been demonstrated that the determination of Pb, Cd, Zn, Mn and Cu in various matrices of mainly biological origin is possible and practicable by means of solid sampling autoprobe GFAAS. Accuracy and precision are comparable to known solid sampling GFAAS systems.

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Herrn Dr. A. Rosopulo gewidmet     

Method development for the determination of thallium in coal using solid sampling graphite furnace atomic absorption spectrometry with continuum source,high-resolution monochromator and CCD array detector

The determination of thallium by graphite furnace atomic absorption spectrometry (GFAAS) is plagued by several difficult-to-control interferences. High-resolution continuum-source GFAAS, a technique not yet commercially available, was used to investigate and eliminate spectral interferences, and to develop a reliable method for the determination of thallium in coal using direct solid sampling. The resolution of 2.1 pm per pixel, and the display of the spectral environment ±0.2 nm on both sides of the analytical line were ideally suited for that purpose. The thallium signal was preceded by excessive non-specific absorption due to the coal matrix when pyrolysis temperatures ≤600 °C were used, and a characteristic molecular absorption with pronounced fine structure was following the atomic absorption. With a pyrolysis temperature of 700 °C the non-specific absorption at the beginning of the atomization stage could be eliminated, and using an atomization temperature of 1700 °C, and no modifier, the atomic absorption could be separated in wavelength and in time from the molecular structures, making possible an interference-free determination of thallium, using Pixel 260 at 276.8085 nm for background correction. The results obtained for 11 coal samples and one coal fly ash were in agreement at a 95% confidence level without a modifier, with palladium added in solution, and with ruthenium as permanent modifier, respectively, using aqueous standards for calibration. A characteristic mass of m₀=12 pg and 5.5 pg was obtained with the center pixel only, and the center pixel ±1, respectively. The precision, expressed as relative standard deviation was typically better than 5%, and the limit of detection, based on three times the standard deviation of the coal with the lowest analyte content, was 0.01 μg g⁻¹.     

Study on the simultaneous determination of some essential and toxic trace elements in honey by multi-element graphite furnace atomic absorption spectrometry

A multi-element graphite furnace atomic absorption spectrometry (GFAAS) method was elaborated and applied for the simultaneous determination of As, Cd, Cr, Cu, and Pb in various kinds of honey samples (acacia, floral, linden, rape, and milkweed) using the transversally heated graphite atomiser (THGA) with end-capped tubes and integrated graphite platforms (IGPs). For comparative GFAAS analysis, direct (without digestion) and indirect (with digestion in a microwave oven) sample preparation procedures were tested. The effects of several chemical modifiers, such as NH₄H₂PO₄, NH₄H₂PO₄-Mg(NO₃)₂, and Pd(NO₃)₂-Mg(NO₃)₂, were studied to obtain optimal pyrolysis and atomization conditions for the set of analytes studied. The most efficient modifier was proved to be the mixture of 5 μg Pd (applied as nitrate) plus 3 μg Mg(NO₃)₂, allowing the optimal 600 °C pyrolysis and 2300 °C atomization temperatures. To prevent the sputtering and foaming of the matrix during the drying and pyrolysis steps of the furnace heating program, the sample and modifier solutions (20 + 5 μl, respectively) were dispensed together onto the IGP of the THGA pre-heated at 80 °C.The effect of increasing concentration of honey matrix was studied on the integrated absorbance (A_int) signals of analytes. The A_int signals of Cr and Pb were not altered up to 10% (m/v) matrix content in the sample solutions. The matrix effect was slightly suppressive on the A_int signals of As, Cd, and Cu above 2% (m/v) honey concentration. The recovery was found to be ranged between 85 and 115% for Cd, Cr, Cu, and Pb, whereas it was a lower, compromise value of 70-99% for As. The limit of detection (LOD) data were 1, 0.04, 0.09, 0.3, and 0.6 μg l⁻¹ for As, Cd, Cr, Cu, and Pb, respectively, which values correspond to 20, 0.8, 1.8, 5.3, and 12 ng g⁻¹, respectively, in the solid samples. The characteristic masses were found to be 21 pg As, 1.3 pg Cd, 4 pg Cr, 12 pg Cu, and 33 pg Pb. The As, Cd, Cr, Cu, and Pb contents of the studied 42 honey samples varied significantly, i.e. from below the LOD up to 13, 3.3, 109, 445, and 163 ng g⁻¹, respectively.     

Direct analysis of solid samples by graphite furnace atomic absorption spectrometry with a transversely heated graphite atomizer and D2-background correction system (SS GF-AAS)

An instrumental design for the analysis of heavy metals in solid samples (certified reference materials, river sediments, cements) by direct graphite furnace atomic absorption spectroscopy (SSGF-AAS) is presented and outlined. A high performance atomic absorption spectrometer with a D₂-background corrector and a transversely heated graphite atomizer was modified. Solid sampling was achieved by a mechanical module combined with an ultra microbalance. Cadmium, lead and chromium in different samples (sample weights between 20–400 μg) have been determined in the μg/g- to ng/g-range with the graphite-platform technique. Different ways of calibration and inhomogeneity problems are discussed. The precision of SSGF-AAS is equal to the precision of the conventional AAS-technique with chemical digestion (microwave digestion system, Zeeman-AAS). It is shown that SSGF-AAS is a reasonable alternative to the conventional technique for selected analytical problems.     

Direct analysis of solid samples by graphite furnace atomic absorption spectrometry with a transversely heated graphite atomizer and D2-background correction system (SS GF-AAS)

An instrumental design for the analysis of heavy metals in solid samples (certified reference materials, river sediments, cements) by direct graphite furnace atomic absorption spectroscopy (SSGF-AAS) is presented and outlined. A high performance atomic absorption spectrometer with a D₂-background corrector and a transversely heated graphite atomizer was modified. Solid sampling was achieved by a mechanical module combined with an ultra microbalance. Cadmium, lead and chromium in different samples (sample weights between 20–400 μg) have been determined in the μg/g- to ng/g-range with the graphite-platform technique. Different ways of calibration and inhomogeneity problems are discussed. The precision of SSGF-AAS is equal to the precision of the conventional AAS-technique with chemical digestion (microwave digestion system, Zeeman-AAS). It is shown that SSGF-AAS is a reasonable alternative to the conventional technique for selected analytical problems. Received: 19 February 1997 / Revised: 30 May 1997 / Accepted: 4 June 1997     

固体进样-石墨炉原子吸收光谱法直接测定玉米中的铅

建立了一种直接固体进样-石墨炉原子吸收光谱法测定玉米中铅的方法。方法的相对标准偏差为4.8%~11.3%(n=9),铅的检出限为0.0062ng,测定结果与国标法一致。与湿法消解方法相比较,本方法样品不用进行化学前处理而直接测定,避免了样品的稀释以及试剂的交叉污染带来的分析误差。     

Study of a microwave induced argon plasma sustained in a TE101 cavity as spectrochemical emission source coupled with graphite furnace evaporation

The argon MIP sustained in a TE₁₀₁ cavity has been evaluated as a spectrochemical radiation source and its analytical performance in combination with graphite furnace evaporation has been studied. A quartz discharge tube with a side arm is used, through which the sample vapour from the furnace is introduced by the carrier gas. A stable quasi-toroidal rotating plasma with a central channel could be maintained within a wide range of operating conditions. Under the compromise conditions established, the detection limits for Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Tl are 4, 120, 8, 305, 47, 24, 55, 11, 220, 56 and 28 pg, respectively. The presence of Na results in line intensity enhancements in most cases, which are proportional to the Na amount in the range of 60 ng to 10 μg. By the addition of microgram amounts of Pd, acting partly as a chemical modifier in the furnace and eventually as a buffer in the plasma, the matrix effect caused by Na could be eliminated or largely reduced. The present system has been applied to the determination of 16–800 μg/g amounts of Cu, Fe and Mn in a certified tea sample, and 0.35–71 μg/g amounts of Ag, Cu, Fe, Mn and Pb in a certified human hair sample.     

石墨炉原子吸收光谱法测定中药口服液中的铬铅镉

利用石墨炉原子吸收光谱法测定,采用常温消解和密闭微波消解等方式处理口服液样品,并进行比较。结果表明,采用HNO3 HClO4 H2O2作为消解试剂用常温消解方式进行消解后,可不加基体改进剂直接进行测定,在此基础上研究了石墨炉原子吸收测定的最佳条件。应用这种方法测定了双黄连、清开灵、生脉饮和抗病毒口服液中痕量镉、铬和铅,RSD小于5．0％,回收率在83．4％～113％。     

石墨炉原子吸收光谱法测定红薯粉丝中的痕量铅含量

为建立对红薯粉丝中有害元素铅含量的测定方法,采用微波消解法处理红薯粉丝样品,加入2％NH4H2PO4和0．2％Mg（NO3）：混合液作为基体改进剂,用石墨炉原子吸收分光光度法测定了红薯粉丝中铅含量。结果表明,红薯粉丝样品中铅在2．0—40．0ng／mL的范围内吸光度与含量呈良好的线性关系（r=0．9956）,平均回收率为98．06％,RSD=1．67％（n=5）。可见该法简单、准确,可作为检测红薯粉丝中铅含量的方法。