Internal standardization and least-squares background correction in high-resolution continuum source flame atomic absorption spectrometry to eliminate interferences on determination of Pb in phosphoric acid

In this work the least-squares background correction (LSBC) and internal standardization (IS) techniques were combined to eliminate spectral and transport interferences in the determination of Pb in phosphoric acid by high-resolution continuum source atomic absorption spectrometry (HR-CS AAS). Blanks, samples and reference solutions [0.10–1.00 mg L^− 1 Pb in 1% (v/v) HNO₃] were spiked with 4.00 mg L^− 1 Co used as internal standard. For absorbance measurements at the wavelength integrated absorbance equivalent to 9 pixels, correlations between the ratio of absorbance of Pb to absorbance of Co and the analyte concentration were close to 0.9992. Relative standard deviations of measurements varied from 0.6 to 4% and 1 to 7% (n = 12) without and with IS/LSBC techniques, respectively. Recoveries for Pb spikes were in the 96–104% and 76–180% range with and without IS/LSBC, respectively. The limit of detection improved with IS/LSBC techniques. Accuracy of the proposed method was checked for the determinations of Pb in commercial phosphoric acid samples and results obtained with IS were better than those without IS.     

Solid phase extraction of trace amounts of Pb(II) in opium, heroin, lipstick, plants and water samples using modified magnetite nanoparticles prior to its atomic absorption determination

A new, simple, fast and reliable solid-phase extraction method has been developed for separation/preconcentration of trace amounts of Pb(II) using dithizone/sodium dodecyl sulfate-immobilized on alumina-coated magnetite nanoparticles, and its determination by flame atomic absorption spectrometry (FAAS) and graphite furnace atomic absorption spectrometry (GFAAS) after eluting with 4.0?mol?L^?1 HNO₃. Optimal experimental conditions including pH, sample volume, eluent concentration and volume, and co-existing ions have been studied and established. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range and relative standard deviation of Pb(II) using FAAS technique were 280 (for 560?mL of sample solution), 0.28?ng?mL^?1, 1.4?C70?ng?mL^?1 and 4.6% (for 10?ng?mL^?1, n?=?10), respectively. These analytical parameters using GFAAS technique were 300 (for 600?mL of sample solution), 0.002?ng?mL^?1, 0.006?C13.2?ng?mL^?1 and 3.1% (for 5?ng?mL^?1, n?=?10), respectively. The presented procedure was successfully applied for determination of Pb(II) content in opium, heroin, lipstick, plants and water samples.     

Determination of macro- and micronutrients in plant leaves by high-resolution continuum source flame atomic absorption spectrometry combining instrumental and sample preparation strategies

A method for determination of B, Ca, Cu, Fe, K, Mg, Mn, Mo, P, S and Zn in plant tissues by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) is proposed. This method is based on special features of HR-CS-AAS, such as side pixel registration, wavelength integrated absorbance, and molecular absorption bands, for determining macro- and micronutrients in foliar analysis without requiring several different strategies for sample preparation and adjustment of the analytes concentration ranges. Plant samples were analyzed and results for certified materials were in agreement at a 95% confidence level (paired t-test) with reference values. Recoveries of analytes added to plant digests varied within the 82–112% interval. Relative standard deviations (n = 12) were lower than or equal to 5.7% for all analytes in all concentration ranges.     

Investigation of artifacts caused by deuterium background correction in the determination of phosphorus by electrothermal atomization using high-resolution continuum source atomic absorption spectrometry

The artifacts created in the measurement of phosphorus at the 213.6-nm non-resonance line by electrothermal atomic absorption spectrometry using line source atomic absorption spectrometry (LS AAS) and deuterium lamp background correction (D₂ BC) have been investigated using high-resolution continuum source atomic absorption spectrometry (HR-CS AAS). The absorbance signals and the analytical curves obtained by LS AAS without and with D₂ BC, and with HR-CS AAS without and with automatic correction for continuous background absorption, and also with least-squares background correction for molecular absorption with rotational fine structure were compared. The molecular absorption due to the suboxide PO that exhibits pronounced fine structure could not be corrected by the D₂ BC system, causing significant overcorrection. Among the investigated chemical modifiers, NaF, La, Pd and Pd + Ca, the Pd modifier resulted in the best agreement of the results obtained with LS AAS and HR-CS AAS. However, a 15% to 100% higher sensitivity, expressed as slope of the analytical curve, was obtained for LS AAS compared to HR-CS AAS, depending on the modifier. Although no final proof could be found, the most likely explanation is that this artifact is caused by a yet unidentified phosphorus species that causes a spectrally continuous absorption, which is corrected without problems by HR-CS AAS, but which is not recognized and corrected by the D₂ BC system of LS AAS.     

Preconcentration of trace elements in potable liquids by means of a liquid membrane emulsion for flame atomic absorption determination

Summary A liquid membrane emulsion was developed for the simultaneous extraction and preconcentration of traces of Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn in potable liquids. After preconcentration, the eight elements were determined by flame atomic absorption spectrometry (FAAS). The results of analyses of potable water, beer and soft drinks, each from five or six different sources are listed. Data from the preconcentration method were compared with corresponding data obtained from the direct determination of the elements by graphite furnace atomic absorption spectrometry (GFAAS). Differences in results for trace elements between the liquid membrane emulsion-FAAS method and the GFAAS method were in the ranges of ±10% (water), ±9% (beer) and ±14% (soft drinks) for most of the trace elements. The satisfactory agreement meant that analyses of such liquids for trace elements can be carried out accurately with less expensive and widely available FAAS equipment.     

Determination of Cd, Co, Cu, Mn, Ni, Pb, and Zn by Inductively Coupled Plasma Mass Spectroscopy or Flame Atomic Absorption Spectrometry after On-line Preconcentration and Solvent Extraction by Flow Injection System

The concentrations of Cd, Co, Cu, Mn, Ni, Pb, and Zn in natural and sea waters are too low to be directly determined with by flame atomic absorption spectrometry (FAAS) or graphite furnace atomic absorption spectrometry (GFAAS). Specific sample preparations are requested that make possible the determination of these analytes by preconcentration or extraction. These techniques are affected by severe problems of sample contamination. In this work Cd, Co, Cu, Mn, Ni, Pb, and Zn were determined by inductively coupled plasma mass spectroscopy (ICP-MS) or by atomic absorption spectrometry, in fresh and seawater samples, after on-line preconcentration and following solvent elution with a flow injection system. Bonded silica with octadecyl functional group C₁₈, packed in a microcolumn of 100-μl capacity, was used to collect diethyldithiocarbamate complexes of the heavy metals in aqueous solutions. The metals are complexed with a chelating agent, adsorbed on the C₁₈column, and eluted with methanol directly in the flow injection system. The methanolic stream can be addressed to FAAS for direct determination of Cu, Ni, and Zn, or collected in a vial for successive analysis by GFAAS. The eluted samples can be also dried in a vacuum container and restored to a little volume with concentrated HNO₃and Milli-Q water for analysis by ICP-MS or GFAAS.     

微波消解-高分辨连续光源原子吸收光谱法测定锁阳和韭菜籽中的重金属元素含量

利用微波消解-高分辨连续光源原子吸收光谱法测定锁阳、韭菜籽两种中药材中铜(Cu)、铅(Pb)、镉(Cd)、铬(Cr)、砷(As)和汞(Hg)的含量.采用微波消解进行样品前处理,火焰原子吸收法测定其中的Cu含量,石墨炉原子吸收法测定Pb、Cd和Cr含量,氢化物发生原子吸收法测定As、Hg含量.方法线性关系良好,相关系数R^2大于0.999,加标回收率为95.61%~100.1%,RSD为0.8%~3.3%,测得锁阳和韭菜籽中Cu、Pb、Cd、Cr、As和Hg的含量值均低于《药用植物及制剂进口绿色行业标准》和食品安全国家标准《食品中污染物限量》(GB2762-2012)中规定的限量指标.方法分析速率快、干扰少、精密度高,适用于中药材中重金属含量的测定.     

Determination of cobalt in biological samples by line-source and high-resolution continuum source graphite furnace atomic absorption spectrometry using solid sampling or alkaline treatment

Two procedures for the determination of Co in biological samples by graphite furnace atomic absorption spectrometry (GF AAS) were compared: solid sampling (SS) and alkaline treatment with tetramethylammonium hydroxide (TMAH) using two different instruments for the investigation: a conventional line-source (LS) atomic absorption spectrometer and a prototype high-resolution continuum source atomic absorption spectrometer. For the direct introduction of the solid samples, certified reference materials (CRM) were ground to a particle size ≤50 μm. Alkaline treatment was carried out by placing about 250 mg of the sample in polypropylene flasks, adding 2 mL of 25% m/v tetramethylammonium hydroxide and de-ionized water. Due to its unique capacity of providing a 3-D spectral plot, a high-resolution continuum source (HR-CS) graphite furnace atomic absorption spectrometry was used as a tool to evaluate potential spectral interferences, including background absorption for both sample introduction procedures, revealing that a continuous background preceded the atomic signal for pyrolysis temperatures lower than 700 °C. Molecular absorption bands with pronounced rotational fine structure appeared for atomization temperatures >1800 °C probably as a consequence of the formation of PO. After optimization had been carried out using high resolution continuum source atomic absorption spectrometry, the optimized conditions were adopted also for line-source atomic absorption spectrometry. Six biological certified reference materials were analyzed, with calibration against aqueous standards, resulting in agreement with the certified values (according to the t-test for a 95% confidence level) and in detection limits as low as 5 ng g⁻¹.     

The problem of arsenic interference in the analysis of Cd to evaluate its extractability in soils contaminated by arsenic

The arsenic (As) spectral interference observed in the determination of cadmium (Cd) by inductively coupled plasma atomic emission spectrometry (ICP-AES) was studied in atomic absorption spectrometry (AAS) using flame (FAAS) and graphite furnace (GFAAS) as atomizers. The soils of 15 kitchen gardens located near two smelters in the North of France were selected according the ratio As/Cd. Four different extracting solutions usually used to evaluate the mobility of Cd were chosen to extract Cd from these soil samples: citric acid 0.11 M, acetic acid 0.11 M, calcium chloride 0.01 M and water. The quantitative determinations of Cd in the 15 soils for each solvent were investigated by ICP-AES at two lines (228.802 and 214.438 nm) and by FAAS or GFAAS with two-way background compensation. Compared to the Cd concentrations measured in the acid solutions and in the CaCl₂ solution after the addition of a chemical modifier, it was clearly demonstrated that the high-speed self-reversal background compensation (HSSR-method) was the method of choice to eliminate the spectral interference of As during Cd determination by FAAS and by GFAAS. In water, it was shown that the deuterium lamp used for the background compensation (D₂-method) was able to eliminate the most of the As interference. In comparison with Cd concentrations in water after adding a chemical modifier, those obtained with the HSSR-method were similar and a very good correlation was obtained between these two methods (R² = 0.995). It was therefore established that the HSSR-method would be able to replace the chemical modifiers to eliminate As interference in the determination of Cd-extractable from As contaminated soils.     

Direct determination of Cu,Mn, Pb,and Zn in beer by thermospray flame furnace atomic absorption spectrometry

In this work, thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was employed for Cu, Mn, Pb, and Zn determination in beer without any sample digestion. The system was optimized and calibration was based on the analyte addition technique. A sample volume of 300 μl was introduced into the hot Ni tube at a flow-rate of 0.4 ml min⁻¹ using 0.14 mol l⁻¹ nitric acid solution or air as carrier. Different Brazilian beers were directly analyzed after ultrasonic degasification. Results were compared with those obtained by graphite furnace atomic absorption spectrometry (GFAAS). The detection limits obtained for Cu, Mn, Pb, and Zn in aqueous solution were 2.2, 18, 1.6, and 0.9 μg l⁻¹, respectively. The relative standard deviations varied from 2.7% to 7.3% (n=8) for solutions containing the analytes in the 25–50 μg l⁻¹ range. The concentration ranges obtained for analytes in beer samples were: Cu: 38.0–155 μg l⁻¹; Mn: 110–348 μg l⁻¹, Pb: 13.0–32.9 μg l⁻¹, and Zn: 52.7–226 μg l⁻¹. Results obtained by TS-FF-AAS and GFAAS were in agreement at a 95% confidence level. The proposed method is fast and simple, since sample digestion is not required and sensitivity can be improved without using expensive devices. The TS-FF-AAS presented suitable sensitivity for determination of Cu, Mn, Pb, and Zn in the quality control of a brewery.     

Determination of trace elements in lithium niobate crystals by solid sampling and solution-based spectrometry methods

Solid sampling (SS) graphite furnace atomic absorption spectrometry (GFAAS) and solution-based (SB) methods of GFAAS, flame atomic absorption spectrometry (FAAS), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) were elaborated and/or optimized for the determination of Cr, Fe and Mn trace elements used as dopants in lithium niobate optical crystals.     

Determination of lead traces in water and liqueurs by derivative atom trapping flame atomic absorption spectrometry

 A new method for the direct determination of lead traces using derivative atom trapping flame atomic absorption spectrometry (DAT-FAAS) with an improved water-cooled stainless steel trapping equipment in an air-acetylene flame was investigated. The optimum conditions concerning the sensitivity were studied. For a 1 min collection, the characteristic concentration (given as derivative absorbance of 0.0044) and the detection limit (3s) were 1.4 ng/mL and 0.27 ng/mL, respectively. This is 361 and 74-fold better than those of the conventional flame atomic absorption spectrometry (FAAS) and comparable to those of graphite furnace atomic absorption spectrometry (GFAAS). The detection limit and sensitivity of DAT-FAAS for a 3 min collection time were 2 and 3 orders of magnitude higher than those of conventional FAAS. The present method was applied to the determination of lead in water and liqueur samples with a recovery range of 94–108% and a relative standard deviation of 3.5–5.6%. Received: 10 January 1996/Revised: 9 December 1996/Accepted: 20 December 1996     

Sequential determination of platinum, ruthenium, and molybdenum in carbon-supported Pt, PtRu, and PtMo catalysts by atomic absorption spectrometry

A simple accurate and precise analytical method for the determination of platinum, ruthenium, and molybdenum in Pt, PtRu, and PtMo nanoparticles catalysts deposited on high-surface area carbon by flame atomic absorption spectrometry (FAAS) and graphite furnace atomic absorption spectrometry (GFAAS) is described. The complete digestion of samples (0.010-0.020 g), which contain noble metals (NMs) in the range between 0 and 30% in combination among them or with other non-NMs, is obtained under mild conditions using both concentrated HCl and HCl+HNO₃ (1+1 (v/v)) mixture to boiling for 30 min in an open vessel. Carbon is separated from the solution by filtering it. Under optimized conditions of the flame, the poor sensitivity of platinum is enhanced 50-fold in presence of 1% (m V⁻¹) ascorbic acid, whereas the analytical signal of ruthenium increased by the presence of co-existing platinum. Any kind of interference is observed on the analytical signal of molybdenum. Recovery test obtained by analyzing commercial powder catalysts ranged from 99 to 101%. The precision, expressed as relative standard deviation of five measurements, is better than 1%. Electrode catalysts, made by using the carbon-supported platinum-based powder catalysts, have been analyzed for the metal loadings onto the electrode by GFAAS after dissolution under the same conditions used for the powder catalysts. The precision, expressed as relative standard deviation of three measurements, is better than 2%.     

The synthesis of new polymeric sorbent and its application in preconcentration of cadmium and lead in water samples

Metal determinations at low concentration levels (≤ng mL⁻¹) comprise one of most important targets in analytical chemistry. This interest also increases in different areas such as biology, medicine, environment and food samples. In spite of inherent high sensitivities obtained for electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma-mass spectrometry (ICP-MS), these techniques have some limitations depending on the concomitants. As a result, interest in preconcentration techniques still continues increasingly for trace metal determinations by flame atomic absorption spectrometry (FAAS) due to the high accuracy of this method.In this work, thioureasulfonamide resin was synthesized, characterized and applied as a new sorption material for determinations of cadmium and lead in water samples. The method is based on the sorption of Cd and Pb ions on the synthesized resin without using any complexing reagent. The optimization of experimental conditions was performed using factorial design including pH, amount of resin, contact time, first sample volume and final eluent volume. Using the experimental conditions defined in the optimization, the method was applied to the determination and preconcentration of Cd and Pb at ng mL⁻¹ level in natural water. Flame AAS was used for trace metal determinations. This method exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent and optimum pH of solution presents in acidic media. Consequently, 600- and 360-fold improvements in the sensitivity of FAAS were achieved by combining the slotted tube atom trap-atomic absorption spectrometry (STAT-FAAS) and the purposed enrichment method for Cd and Pb, respectively.     

Synthesis, characterization and thermal behaviour of solid-state compounds of folates with some bivalent transition metals ions

Solid-state M–L compounds, where M stands for bivalent Mn, Co, Ni, Cu and Zn and L is folate (C₁₉H₁₇N₇O₆)_, have been synthesized. Simultaneous thermogravimetry and differential scanning calorimetry (TG–DSC), X-ray powder diffractometry, infrared spectroscopy (FTIR), TG–DSC coupled to FTIR, elemental analysis and high-resolution continuum source flame atomic absorption spectrometry technique (HR-CS FAAS) were used to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the composition, dehydration, thermal stability and thermal decomposition.     

Simultaneous Voltammetric Determination of Zn(II), Pb(II), Cu(II), and Hg(II) in Ethanol Fuel Using an Organofunctionalized Modified Graphite‐Polyurethane Composite Disposable Screen‐Printed Device

A disposable screen‐printed device containing working, auxiliary, and reference electrodes is proposed for the simultaneous voltammetric determination of Zn(II), Pb(II), Cu(II), and Hg(II) in ethanol fuel. The working electrode was printed using an ink modified with 2‐benzothiazole‐2‐thiol organofunctionalized SBA‐15 silica, in order to increase sensitivity. The performance of this electrode was compared with that of bare and SBA‐15‐modified electrodes. After optimizing the experimental parameters, the device was applied in determination of the analytes in commercial ethanol fuel samples, using 0.10 mol L^?1 KCl/ethanol ratios of 30 : 70 (v/v), with [H⁺]=10^?5 mol L^?1. After 5 min of preconcentration at ? 1.3 V (vs. pseudo‐Ag/AgCl), four well‐resolved signals were obtained, enabling simultaneous determination of the four analytes using a differential pulse anodic stripping voltammetry (DPASV) procedure. The limits of detection were 0.30, 0.065, 0.030, and 0.046 µmol L^?1 for Zn(II), Pb(II), Cu(II), and Hg(II), respectively. The results of these analyses were in agreement with those obtained using graphite furnace atomic absorption spectroscopy (GFAAS) for Pb(II), Cu(II), and Hg(II), and high‐resolution continuum source flame atomic absorption spectrometry (HR‐CS‐FAAS) for Zn²⁺, at a 95 % confidence level. Analytes originally present in the samples could be detected, and the interference of some cations and anions was evaluated.     

Hollow fiber liquid phase microextraction combined with graphite furnace atomic absorption spectrometry for the determination of methylmercury in human hair and sludge samples

Two methods, based on hollow fiber liquid–liquid–liquid (three phase) microextraction (HF-LLLME) and hollow fiber liquid phase (two phase) microextraction (HF-LPME), have been developed and critically compared for the determination of methylmercury content in human hair and sludge by graphite furnace atomic absorption spectrometry (GFAAS). In HF-LPME, methylmercury was extracted into the organic phase (toluene) prior to its determination by GFAAS, while inorganic mercury remained as a free species in the sample solution. In HF-LLLME, methylmercury was first extracted into the organic phase (toluene) and then into the acceptor phase (4% thiourea in 1 mol L^− 1 HCl) prior to its determination by GFAAS, while inorganic mercury remained in the sample solution. The total mercury was determined by inductively coupled plasma-mass spectrometry (ICP-MS), and the levels of inorganic mercury in both HF-LLLME and HF-LPME were obtained by subtracting methylmercury from total mercury. The factors affecting the microextraction of methylmercury, including organic solvent, extraction time, stirring rate and ionic strength, were investigated and the optimal extraction conditions were established for both HF-LLLPME and HF-LPME. With a consumption of 3.0 mL of the sample solution, the enrichment factors were 204 and 55 for HF-LLLPME and HF-LPME, respectively. The limits of detection (LODs) for methylmercury were 0.1 μg L^− 1 and 0.4 μg L^− 1 (as Hg) with precisions (RSDs (%), c = 5 μg L^− 1 (as Hg), n = 5) of 13% and 11% for HF-LLLPME–GFAAS and HF-LPME–GFAAS, respectively. For ICP-MS determination of total mercury, a limit of detection of 39 ng L^− 1 was obtained. Finally, HF-LLLME–GFAAS was applied to the determination of methylmercury content in human hair and sludge, and the recoveries for the spiked samples were in the range of 99–113%. In order to validate the method, HF-LLLME–GFAAS was also applied to the analysis of a certified reference material of NRCC DORM-2 dogfish muscle, and the determined values were in good agreement with the certified values.     

Feasibility of internal standardization in the direct and simultaneous determination of As, Cu and Pb in sugar-cane spirits by graphite furnace atomic absorption spectrometry

Bismuth and Sb were evaluated as internal standards (IS) to minimize matrix effects on the direct and simultaneous determination of As, Cu, and Pb in cachaça by graphite furnace atomic absorption spectrometry using W-coated platform plus Pd-Mg(NO₃)₂ as modifier. For 20 μL injected sample, calibration within the 0.5-10 μg L⁻¹ As, 100-1000 μg L⁻¹ Cu and 0.5-30 μg L⁻¹ Pb intervals were established using the ratios As absorbance to Sb absorbance, Cu absorbance to Bi absorbance and Pb absorbance to Bi absorbance versus analytes concentration, respectively. Typical linear correlations of 0.998, 0.999 and 0.999 were, respectively, obtained. The proposed method was applied for direct determination of As, Cu and Pb in 10 commercial cachaça samples and results were in agreement with those obtained by inductively coupled plasma mass spectrometry at 95% confidence level. The found characteristic masses were 30 pg As, 274 pg Cu and 39 pg Pb. The useful lifetime of the graphite tube was around 760 firings. Recoveries of As, Cu and Pb added to cachaça samples varied, respectively, from 98% to 109%, 97% to 108% and 98% to 104% with internal standards and from 48% to 54%, 53% to 92% and 62% to 97% without internal standards. The limits of detection were 0.13 μg L⁻¹ As, 22 μg L⁻¹ Cu and 0.05 μg L⁻¹ Pb. The relative standard deviations (n = 12) for a spiked sample containing 20 μg L⁻¹ As, Pb and 500 μg L⁻¹ Cu were 1.6%, 1.0%, and 1.8% with IS and 4.3%, 5.2%, and 5.5% without IS.     

Determination of cadmium and lead in reference materials by volatile species generation with in situ trapping flame atomic absorption spectrometry

The analytical performance of coupled volatile species generation-integrated atom trap (VSG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of Cd and Pb in reference materials. Lead using formation of PbH₄ and Cd⁰ vapors are atomized in air-acetylene flame-heated IAT. A new design of VSG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube or an “integrated trap”) was investigated. A dramatic improvement in detection limit was achieved compared with that obtained using either of the above atom trapping techniques separately. The concentration detection limits, defined as 3 times the blank standard deviation (3σ), were 0.05 and 0.40 ng mL^− 1 for Cd and Pb, respectively. For a 120 s in situ pre-concentration time, sensitivity enhancement compared to flame AAS, was 500 and 575 folds for Cd and Pb, respectively, using volatile species generation-atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed as RSD, was 4.4% and 4.1% (n = 6) for Cd and Pb, respectively. The designs studied include slotted tube, single silica tube and integrated atom trap-cooled atom traps. The accuracy of method was verified using certified reference materials (PLANTS 3 and IAEA/W-4) by standard addition calibration technique. The measured Cd and Pb contents in two reference materials were in satisfactory agreement with the certified values.     

Design and Critical Evaluation of Improved Electrothermal Vaporization Flame Atomic Absorption/Emission Spectrometry for Direct Determination of Trace Metals in Microliter Samples

Improved tantalum-filament electrothermal vaporization flame atomic absorption spectrometry (ETV-FAAS) was developed and used for the direct determination of trace metals in microliter samples. Studies have been made for optimizing the experimental parameters that affect the performance of sample introduction to the flame. Linear calibration graphs are shown for the elements Mn (10–200 ng), Pb (5–200 ng), Cu (5–100 ng), Cd (5–50 ng), Li (1–20 ng), Na (10–80 ng), and K (10–80 ng), using only 10 μl of standard solutions. The detection limits of the elements by ETV-FAAS were much lower than those of conventional FAAS. Absolute detection limits for all elements studied were less than 0.1 ng. The relative standard deviation values for the elements were <10%. The developed method was also applied to the determination of lead concentration in blood samples.