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The use of ultrasonic treatment for improvement of metrological performance of sorption atomic absorption determination of lead(II) and cadmium(II) traces

100%

Alemasova A. , Belova E.

Open Chemistry

2010

tom 8

nr 1

58-64

The optimal parameters for ultrasonic treatment (frequency 200–300 kHz, intensity 2–4 W cm−2) were obtained to intensify Pb(II) and Cd(II) sorption concentration by carbon sorbent from apricot pit. The combined action of ultrasonic frequency of 18 kHz and 1 MHz on concentrate slurry increases its sedimentation stability from 3 to 180 minutes and decreases Sr value up to 7% at Pb(II), Cd(II) hybrid sorption atomic absorption determination in natural waters, brines, common salt. [...]

Kinetic study of atomization in atomic absorption analysis of solid samples using flame-furnace atomizer

80%

Lugovyy K. , Buhay O. , Alemasova A.

Open Chemistry

2010

tom 8

nr 6

1244-1250

Direct solid sampling analysis in atomic absorption spectrometry using flame-furnace atomizer allows to significantly decrease analysis duration, to avoid sample pollution and to exclude toxic reagents. The choice of chemical modifiers that decreases the detection limit and improves the repeatability of results is based on the mechanism of analyte-free atom formation. The kinetic approach developed here allows determination of pre-exponential factors k0 and apparent activation energies Ea of the atomization processes for Pb(II) and Cd(II) compounds and enables use of CaCO3 and KHF2 as effective chemical modifiers for soil samples. A fast and precise technique for lead and cadmium determination in soils using the proposed chemical modifiers was developed.

Lead and cadmium atomic absorption determination in solid carbonized food samples using flame-furnace atomizer

80%

Lugovyy K. , Buhay O. , Alemasova A.

Open Chemistry

2014

tom 12

nr 3

386-390

Direct atomic absorption solid sampling analysis using flame-furnace atomizer enables a significant decrease in the analysis duration, to avoid sample pollution and to exclude toxic reagents. The selection of the chemical modifiers decreasing the detection limit and improving the results repeatability is based on the analyte’s free atoms formation mechanism. The developed kinetic approach has allowed to determine pre-exponential factors k0 and apparent activation energies Ea of atomization processes for Pb(II) and Cd(II) compounds and to propose effective chemical modifiers sodium N,N-diethyldithiocarbamate and urea for food samples. The express and precision technique for lead and cadmium determination in food, using proposed chemical modifiers and carbonization techniques was developed.

Extractants selection for hyphenated electrothermal atomic absorption method

80%

Alemasova A. , Alemasova N. , Pupyshev A.

Open Chemistry

2013

tom 11

nr 11

1852-1859

The theoretical approach for extractants selection during hyphenated atomic absorption determination of highly volatile metals (Pb, Cd), hydride- (Sb, Bi) and carbide-forming (Cr) metals using thermodynamic modelling was proposed. The calculated parameter - maximum pyrolysis temperature - can be used for selection of the extractants and chemical modifiers. Using this approach the antimony extract with Brilliant green was modified for which the 1.8-fold sensitivity and 2.6-fold repeatability decreasing while extract sampling in graphite furnace was observed. A chemical modifier - mixture of hydrazine nitrate with the palladium(II) complex with Xylenol orange - was theoretically selected and experimentally tested, which allowed to enhance the maximum pyrolysis temperature on 200°C, to eliminate extract matrix influence. Using this modifier two-fold increasing in sensitivity and 3-fold decreasing in relative standard deviation was achieved while extraction atomic absorption determination. [...]