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Journal ArticleDOI

Determination of Ca, Cu, Fe and Mg in fresh and processed meat treated with tetramethylammonium hydroxide by atomic absorption spectrometry

01 Oct 2011-Journal of the Brazilian Chemical Society (Brazilian Chemical Society)-Vol. 22, Iss: 10, pp 1850-1857

AbstractUm metodo simples para o tratamento de amostras de carne fresca e processada com hidroxido de tetrametilamonio (TMAH) e proposto para a determinacao de Ca, Fe e Mg por espectrometria de absorcao atomica com chama (FAAS) e Cu por espectrometria de absorcao atomica com forno de grafite (GFAAS). A exatidao foi avaliada por comparacao dos resultados usando outros dois procedimentos de preparo de amostra e por analise de materiais de referencia certificados. Nao houve diferenca significativa entre os resultados obtidos, em um nivel de confianca de 95%. Os limites de deteccao para Ca, Cu, Fe e Mg foram 45,0, 0,2, 16,0 e 0,3 µg g -1 , respectivamente. A espectrometria de absorcao atomica de alta resolucao com fonte continua em forno de grafite (HR-CS GFAAS) foi empregada para avaliar as interferencias espectrais na determinacao de Cu. Entretanto, nenhuma interferencia foi encontrada. O metodo proposto e simples, rapido e confiavel para analise de produtos carneos e nao requer o uso de equipamentos especiais nem de acidos fortes no preparo das amostras. A simple method for treating fresh and processed meat with tetramethylammonium hydroxide (TMAH) is proposed for the determination of Ca, Fe and Mg by flame atomic absorption spectrometry (FAAS) and Cu by graphite furnace atomic absorption spectrometry (GFAAS). The accuracy was evaluated by comparison of the results by using two other sample preparation procedures and by the analysis of certified reference materials. No significant differences between the results were found at the 95% confidence level. Limits of detection for Ca, Cu, Fe and Mg were 45.0, 0.2, 16.0 and 0.3 µg g -1 , respectively. High-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) was employed to evaluate the spectral interference in the determination of Cu. However, no interference was found. The proposed method is simple, fast and reliable for meat products analysis and does not require especial equipment, neither strong acid for sample preparation.

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Journal ArticleDOI
Abstract: The aim of this study was to present three sample preparation methods for the determination of Cd, Pb and Sn in meat by Graphite Furnace Atomic Absorption Spectrometry (GFAAS): acid digestion, solubilization with tetramethylammonium hydroxide and formic acid. For the digestion with HNO3, a conventional open system with a cold finger was used. This system helped to avoid losses of analytes and reagents by volatilization, permitting to operate at high temperatures applied at a digester block and reducing the digestion time (∼1 h). Solubilizations were performed at room temperature. The slurry was left standing overnight and remained closed until achieving complete solubilization. The temperature program of the graphite furnace was optimized for each element in the different means of preparation samples using a mixture of Pd–Mg. The figures of merit were similar for all sample preparation methods evaluated. The limits of detection obtained for the acid digestion procedure were 0.0006, 0.0164 and 0.0520 μg g−1 for Cd, Pb and Sn, respectively. In order to evaluate the accuracy of the results obtained by the three sample preparation methods, recovery tests for four real meat samples were performed and the recoveries ranged from 93.7 to 109%, supporting the accuracy of the method. Also, different certified reference materials of meat were analyzed and the results obtained were in agreement with the certified value at 95% of confidence (t-test). The best results were obtained by the acid digestion procedure with the cold finger system. This procedure is faster, the system is semi-closed with no significant contamination or loss of analytes by volatilization and it provides a better signal/noise ratio.

14 citations


Journal ArticleDOI
15 Jan 2016-Talanta
TL;DR: The determination of Al contaminant and the main component Si in silicon carbide (SiC) nanocrystals with the size-distribution of 1-8nm dispersed in an aqueous solution was developed using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS).
Abstract: The determination of Al contaminant and the main component Si in silicon carbide (SiC) nanocrystals with the size-distribution of 1-8nm dispersed in an aqueous solution was developed using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS). The vaporization/atomization processes were investigated in a transversally heated graphite atomizer by evaporating solution samples of Al and Si preserved in various media (HCl, HNO3). For Si, the best results were obtained by applying a mixture of 5µg Pd plus 5µg Mg, whereas for Al, 10µg Mg (each as nitrate solution) was dispensed with the samples, but the results obtained without modifier were found to be better. This way a maximum pyrolysis temperature of 1200°C for Si and 1300°C for Al could be used, and the optimum (compromise) atomization temperature was 2400°C for both analytes. The Si and Al contents of different sized SiC nanocrystals, dispersed in aqueous solutions, were determined against aqueous (external) calibration standards. The correlation coefficients (R values) of the calibrations were found to be 0.9963 for Si and 0.9991 for Al. The upper limit of the linear calibration range was 2mg/l Si and 0.25mg/l Al. The limit of detection was 3µg/l for Si and 0.5µg/l for Al. The characteristic mass (m0) was calculated to be 389pg Si and 6.4pg Al. The Si and Al content in the solution samples were found to be in the range of 1.0-1.7mg/l and 0.1-0.25mg/l, respectively.

11 citations


Journal ArticleDOI
TL;DR: High-resolution continuum source flame atomic absorption spectrometry can be successfully used for the rapid, multielemental determination of hazardous/priority hazardous metals in soil with similar analytical performances to those in inductively coupled plasma optical emission Spectrometry.
Abstract: The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94–106% in atomic absorption and 97–103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6–5.2% in atomic absorption, similar with that of 1.9–6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference between the two spectrometric methods for 95% confidence interval. High-resolution continuum source flame atomic absorption spectrometry can be successfully used for the rapid, multielemental determination of hazardous/priority hazardous metals in soil with similar analytical performances to those in inductively coupled plasma optical emission spectrometry.

9 citations


Cites methods from "Determination of Ca, Cu, Fe and Mg ..."

  • ...Thus, HRCS GFAAS was mentioned for elemental determination in food after acidic digestion or extraction in tetramethylammonium hydroxide [12-14], airborne particulates [15-18], biological (beans and grain) samples using direct solid sampling [19-21], fertilizer by slurry sampling [22], crude oil [23-26], biodiesel [27] and in whole blood directly in diluted/undiluted samples [28]....

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Journal ArticleDOI
Abstract: Tetramethylammonium hydroxide (TMAH) is one of the most popular methylation reagents that have been increasingly used for the detection of organic compounds within a wide range of samples, such as soil, coal, lacquer, lignin, polymers and for in situ analysis of solid samples by space experiments. The analytical methods and instruments, experimental conditions, and the qualitative and quantitative analysis of organic compounds using TMAH thermochemolysis for the last 10 years were reviewed; additionally, the mechanism of TMAH thermochemolysis and TMAH degradation are overviewed herein. The objective of this paper is to give a broad view of the TMAH thermochemolysis analysis, to demonstrate how the technique can be used for the detection of organics on Mars and other planets, and to promote cooperation between different disciplines which may use thermochemolysis.

6 citations


Journal ArticleDOI
Abstract: Alkaline solubilization with tetramethylammonium hydroxide (TMAH) and ultrasound-assisted extraction as sample preparation procedures were evaluated for the extraction and subsequent determination of Cr and Pb in leather samples by flame atomic absorption spectrometry (FAAS). In the alkaline solubilization with TMAH, 0.10 g of the sample was heated to 95 ± 5 °C for 30 minutes in the presence of 2.75 mol L−1 TMAH in methanol medium. The procedure provided complete solubilization of the sample, resulting in limits of detection of 4 μg g−1 for Cr and 9 μg g−1 for Pb; the obtained RSD values were lower than 9.7%. Ultrasound-assisted extraction was evaluated with aliquots of 0.15 g of the sample, using HNO3, aqua regia and HCl as extraction solutions. However, this procedure was effective only for Pb extraction, using HNO3 and aqua regia as extractants. The limits obtained for Pb detection of 4 μg g−1 and RSD values lower than 3.8% were adequate for the determination. The simplicity of the proposed procedures for sample preparation, the reduced amounts of reagents required, minimizing contamination risks, and the low cost of the required instrumentation make these procedures excellent alternatives for the preparation of leather samples for elementary analysis.

3 citations