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Interference study by arsenic determination using UV-photochemical generation of its volatile species with AAS detection
Smolejová, Jana ; Červený, Václav (advisor) ; Nesměrák, Karel (referee)
This thesis deals with the interference study of the UV-photochemical generation of arsenic volatile species with AAS detection and it searches for a suitable reaction modifier, which would improve sensitivity of the As determination. Interferences were classified into 3 groups according to their influence on the As UV-photochemical volatile species generation. Ni2+ , Cu2+ , Cl− and merkaptoethanol belong among the negative interferents. HNO3, Fe3+ , ethanol, SO4 2− , TiO2 and L-cysteine belong among the low-level interferents. Co2+ , acetonitrile, triethanolamine, selenite and Bi3+ belong to a group, which increases the absorbance of arsenic and could, therefore, be called positive interferents. Concentration of 10 mg l−1 of Bi3+ significantly increases the level of absorbance of arsenic. This effect was utilized during measurement of calibration dependence and Bi3+ ions were used as the reaction modifier. The figures of merit of this method with reaction modifier were obtained. Limit of detection was 18 µg l−1 , limit of quantification was 60 µg l−1 , sensitivity was 1.144·10−3 l µg−1 , repeatability was 4.5 % (relative standard deviation) a linear range was 60 - 500 µg l−1 . We achieved eleven times better absorbance by using this reaction modifier compared to UV-photochemical volatile species...
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