Determination of selected herbicides and phenols in water and soils by solid-phase extraction and high-performance liquid chromatography.

A high-performance liquid chromatography procedure or the determination of the herbicides simazine, propazine, bromacil, metoxuron, and hexazinone is elaborated. Stationary phases RP8 and RP18 and mixtures of methanol-water (2:1 and 1:1, v/v) as a mobile phase are applied for this purpose. The conditions for solid-phase extraction are established, allowing the separation of phenols and herbicides in their mixtures and the extraction of phenols (from river and coke plant water) and herbicides (from the soil samples).

Derivative spectrophotometry in the analysis of mixtures of phenols and herbicides.

Derivative spectrophotometry (zero-crossing technique) was applied to the determination of selected phenols and herbicides in two-component mixtures. Methyl- and chlorophenols (3-methylphenol, 2,3- and 3,4-dimethylphenol, 2,5-, 2,6- and 3,4-dichlorophenol and 2,4,5-trichlorophenol) and triazine, uracil and urea herbicides (simazine, propazine, hexazinone, bromacil and metoxuron) were examined. The RSD values ranged between 0.05 and 4% and the recoveries obtained were between 97 and 110%. The developed derivative spectrophotometric method was also applied as a complementary technique for the separation of overlapping peaks of sample compounds obtained by HPLC with diode-array detection. Metoxuron and 3-methylphenol, metoxuron and 2,5-dichlorophenol and simazine and 2,6-dichlorophenol were determined simultaneously by this method at the level of 1 x 10(-3) g l-1.

Separation and identification of metals in human bones, placenta and milk and in air by adsorption and ion-exchange thin-layer chromatography.

A TLC method for the separation of heavy metals and their complexes with dithizone, 4-(2-pyridylazo)resorcinol and ethylenediaminetetraacetic acid was devised and conditions for the solid-phase extraction of heavy metal ions in human bones, placenta and milk after microwave mineralization and in air after alkaline absorption were elaborated.

UV spectrophotometric investigations of biologically active maleic anhydride copolymers.

UV spectra and absorption coefficients of biologically active copolymers of maleic anhydride with carbohydrates, terpenes and 1,3-dioxane derivatives were measured. The quantitative relationships of absorbance vs concentrations of polymers were determined as well. The possibility of determining the copolymer contamination due to monomers and oligomeric compounds was shown.

Analysis of vanadium-titanium ores and alloys.

A new spectrophotometric method for determining titanium in vanadium-titanium ore with 2,2'-biquinoxalyl was developed. The analytical procedure to dissolve samples and separate titanium from vanadium and tin was elaborated as well. Furthermore, vanadium and iron were determined in the ore investigated.