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A. Kukare, V. Bartkevics and A. Viksna

Development of Methodology for Control of Polycyclic Aromatic Hydrocarbon Content in Food

The assumption that benzo(a)pyrene is the most appropriate marker for all PAHs is questionable. In the research that was performed by the European Food Safety Authority (EFSA), the summary concentration of PAHs including benzo(a)pyrene was 20 times higher than that of benzo(a)pyrene itself. In the routine analyses, the concentration of some other PAHs is more than two times higher than that of benzo(a)pyrene. The aim of the current research was to find a better marker for the reliable characterization of PAHs.

Open access

V. Rudovica, J. Tjutrins, A. Viksna and G. Zarina

Investigation of Optimized Homogenization by Ball Mills for Quantitative Chemical Analysis in Sandy Soils

The efficiency of homogenization was studied by examining particle size distribution and element quantification in the sandy soils using the ball mills. The following parameters were optimized - sample volume, oscillation frequency and grinding time. The homogenized soil fraction with ~ 85% of particles with sizes below 40 μm was established to give high precision and accuracy of quantitative analysis of the results.

Open access

L. Ansone, M. Klavins, A. Robalds and A. Viksna

Water contamination with arsenic compounds is a serious problem. One of the solutions is to develop new sorbents based on natural materials that would be cost-effective and environmentally friendly. New sorbents based on biomaterial impregnation with iron oxyhydroxides have been developed. Raw peat material, iron modified-peat, sand, iron modifiedbiomass (shingles, straw) were used for removal of arsenic compounds. The highest sorption capacity was observed for iron modified-peat. Kinetic studies indicated that most of arsenates were removed within 2 hours, and arsenate sorption on iron modified-peat was characterized by the pseudo-second order rate law.

Open access

V. Rudovica, A. Viksna, J. Katkevich, G. Zarina, J. Bitenieks, J. Zicans, I. Leito and S. Vahur

Studies of Archaeological Bone Structure by Different Analytical Methods

Preservation of the structure of archaeological bones was studied by examining their physicochemical properties. The mechanical properties, and conductivity porosity, crystallinity and content of organic material were evaluated. These parameters were established to be suitable for characterizing changes in the course of time of archaeological bone structure. The obtained results revealed that the elastic modulus and conductivity changes depended on the porosity of bones; and the increase in crystallinity was correlated with a loss of organic matter.

Open access

S. Vorslova, J. Golushko, S. Galushko and A. Viksna

Abstract

We report our experience with highly polar and charged analyte retention parameter prediction for a reversed-phase high-performance liquid chromatographic method. The solvatic retention model has been used to predict retention of phenylisothiocyanate derivatives of 25 natural amino acids under gradient elution conditions. Retention factors have been calculated from molecular parameters of analyte structures and from the column and eluent characteristics. A step-by-step method which includes the first guess prediction of initial conditions from structural formula and fine tuning of the retention model parameters using data from successive runs can substantially save method development time