Stroncio nustatymas vaistažolėse liepsnos atominės absorbcinės spektrometrijos metodu /

Determination of Strontium in Herbs by Flame Atomic Absorption Spectrometry Strontium is an alkaline earth metal. A mineral found in a lead mine, Scotland by A.Crawford in 1790. Strontium is a grey, silvery metal that is softer than calcium. Sr is well known from the minerals SrSO4 and SrCO3. Natural Sr is a mixture of four stable isotopes: 84Sr (0.56%), 86Sr (9.86%),87Sr (7.02%) and 88Sr (82.56%). Strontium accounts for 0.02 - 0.03 % of the Earth’s crust, where it exists as strontium sulfate or strontium carbonate. Strontium can also occur in shales, marls and sandstones. The aim - to explore and optimize the basic conditions for the determination of strontium and prepare the methodic for the determination of strontium in herbs by flame atomic absorbtion spectrometry. A method for the determination of strontium in herbs by flame atomic absorption spectrometry has been suggested. The calibration graph for strontium was linear in the range of 0.25 µg/ml and 4.0 µg/ml. The correlation coefficient was r = 0.9999. The lowest concentration of the strontium that can be confidently detected by the method was 0.07 µg/ml. The effects of various parameters have been determined, such as air 1.29 ∙ 105 Pa and acetylene gas pressure 3.25 ∙ 104 Pa, the influence of nitric, sulphuric acids concentration, the effect of time on the absorbance and the influence of 16 ions on the determination of strontium by atomic absorption spectrometry. The selectivity of the determination of strontium also was studied. The limiting interfering Sr : M ratios ( the determination error ± 10 % ) have been determined. According to the interfering effect examined metals are ordered as: Cr > Co > Fe, Mn > K, Ca, Zn, Cu, Ba, Na, Cd, Al, Bi, Pb, Ni, Mg. The determination of strontium in three herbs has been applied, where the concentration of strontium ranges from 3.38 to 10.63 mg/kg. The relative standard deviation (n = 5) was in the range from 1.07 to 1.35 %. The recovery was found to be ranged between 96 and 101 %.

Grantor dc:publisher

Institutional Repository of Vilnius University

Year dc:date

2016

Author dc:creator

• Baikova, Lorelita,

Contributors dc:contributor

• Tautkus, Stasys

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

lit

Repository record dc:identifier

https://repository.vu.lt/VU:ELABAETD20217453&prefLang=en_US

OAI identifier oai:identifier

oai:vu.lt:elaba:20217453