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On chromium direct ETAAS determination in serum and urine

100%
Todorovska N., Karadjova I., Arpadjan S., Stafilov T.
Open Chemistry
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2007
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vol. 5
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issue 1
230-238
EN
A simple, accurate and reliable method for direct electrothermal atomic absorption spectrometric (ETAAS) determination of chromium in serum and urine samples without any preliminary sample pretreatment is described. Instrumental parameters are optimized in order to define: the most suitable atomizer, optimal temperature program and efficient modifier. An appropriate quantification method is proposed taking into account a matrix interference study. Pyrocoated graphite tubes and wall atomization, pretreatment temperature of 700 °C, atomization temperature of 2600 °C, hydrogen peroxide as modifier and standard addition calibration are recommended. The accuracy of the method proposed for Cr determination in serum and urine was confirmed by comparative analysis of parallel samples after wet or dry ashing as well as by the analysis of two certified reference materials: Serum, Clin Rep 1 and Lypochek Urine, level 1. The detection and determination limits achieved for both matrices are 0.08 µg/L and 0.15 µg/L respectively. The relative standard deviation varied between 15 and 18 % for the chromium content in the samples in the range 0.08–0.2 µg/L and between 4 and 7 % for the chromium content in the range 0.2–2.0 µg/L for both matrices. [...]
2
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On the determination of lead in wine by electrothermal atomic absorption spectrometry

100%
Karadjova I., Cvetković J., Stafilov T., Arpadjan S.
Open Chemistry
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2007
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vol. 5
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issue 3
739-747
EN
The parameters of analytical procedures developed for direct ETAAS determination of Pb in wine are discussed. Atomic absorption spectrometers based on transversal and longitudinal Zeeman effect, wall and integrated platform atomization with two main approaches: (i) measurements in the presence of modifier and (ii) measurements without using any modifier are compared. The optimal temperature programs are defined according to the pre-treatment and atomization curves constructed in the presence of different types of wines. For all investigated instrumental systems, 1:1 dilution of wine sample with 0.2 mol L−1 HNO3 is recommended. Matrix interferences observed, call for standard addition calibration method for Pb quantification in wines. The detection limit (3σ) achieved for wine diluted in the ratio of 1:1 varied from 0.8 to 1.9 μg L−1 depending on the instrument used. The relative standard deviation for the concentration range of 10 to 80 μg L−1 Pb in wine is typically between 4–8%. The accuracy of the analytical procedures recommended was confirmed by comparing the results obtained with those found for wine samples previously digested with HNO3-H2O2 mixture, by added/found method and by parallel analysis using different instruments. A total of 66 wine samples from different regions of Macedonia were analyzed. [...]
3
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Influence of EDTA, carboxylic acids, amino- and hydroxocarboxylic acids and monosaccharides on the generation of arsines in hydride generation atomic absorption spectrometry

88%
Petrov P., Serafimovska J., Arpadjan S., Tsalev D., Stafilov T.
Open Chemistry
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2008
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vol. 6
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issue 2
216-221
EN
The influence of EDTA, carboxylic acids, amino-and hydroxocarboxylic acids, monosaccharides and humic substances on the generation of arsines in hydride generation atomic absorption spectrometry (HGAAS) was investigated. EDTA (0.02 mol L−1), ascorbic acid (0.02 mol L−1) and glucose or fructose (0.2 mol L−1) are useful additives for levelling sensitivities for As(III), monomethylarsonate (MMA) and dimethylarsinate (DMA). The presence of glycine, malonic, tartaric acids, BICIN and soil humin extracts leads to differences in analytical signal response between these arsenic species. An analytical application to the determination of the sum of As(III), monomethylarsonate (MMA) and dimethylarsinate (DMA) as well as the sum of toxicologically relevant hydride forming arsenic fraction As(III) + As(V) + MMA + DMA in EDTA soil/sediment extracts using continuous flow HGAAS was demonstrated. The limit of detection was 0.2 mg kg−1 As. Within-day and between-day precision were in the range 3–7% and 4–10%, respectively, for arsenic contents of 0.7–25 mg kg−1, with recoveries 95–103%. [...]
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