Vladimír Streško

Determination of lead and cadmium in human hair by atomic absorption spectrometric procedures after solid phase extraction

Abstract A separation and preconcentration procedure for Pb and Cd in human hair by using the chelating ion-exchanger, Iontosorb-Oxin, is described. The sorption yield dependence of Pb and Cd, on pH, time, and on the presence of accompanying elements, was investigated. The hair samples were decomposed by microwave irradiation and the determination of lead and cadmium was by flame and electrothermal atomic absorption spectrometry (F-AAS and ETA-AAS, respectively). The precision and accuracy of this procedure were checked by the use of synthetic and certified reference materials. The limit of determination was 1 μg Pb l −1 and 0.1 μg Cd l −1 , respectively. The procedure was applied to samples of human hair.

Determination of rare earth elements in mineral waters by inductively coupled plasma atomic emission spectrometry

A procedure for selective preconcentration of all rare earth elements (REE) in mineral waters on a Dowex cation exchanger has been developed. The precision and accuracy of the procedure were checked on a synthetic standard solution, as well as on real samples using inductively coupled plasma atomic emission spectrometry (ICP-AES). The efficiency of the preconcentration procedure was checked by recovery tests and the reliability of the ICP-AES determination of REE established by comparing the results obtained with those from spectrophotometric analysis.

Determination of beryllium trace contents in mineral waters after preconcentration on a chelating ion-exchanger

SummaryA separation-preconcentration procedure for the determination of Be traces in mineral waters is described. The precision and the accuracy of the procedure were checked by the use of artificial as well as of real samples by AAS-ETA and AES-ICP. On the basis of the results and of their statistical evaluation, the proposed procedure allows to obtain reliable results with the necessary limit of determination and can provide important, till now not accessible information on Be-concentration in waters.

Atomic absorption spectrometric determination of ultra-trace amounts of mercury in waters

A sorption method using the chelating ion exchanger Spheron Thiol was developed for the preconcentration of mercury. To avoid a complicated and problematic desorption, direct atomic absorption spectrometric determination of mercury in the solid sorbent by the use of a TMA-254 spectrometer (trace mercury analyser) was applied. The limit of determination was 0.2 ng l–1 using 1000 ml of water and 0.1 g of Spheron Thiol. The precision of the method expressed as relative standard deviation was 10%. The accuracy of the method was checked by the standard additions technique. The method was applied to the determination of mercury in different types of waters.

Slavikite from Medzev near Košice, Czechoslovakia

A mineralogical description of slavikite formed on pyritized phyllites in Medzev, Eastern Czechoslovakia, is given. It consists of morphological description, refraction indices, data of differential thermal analysis, X-ray powder data and chemical analysis of the mineral.

CORRELATION BETWEEN QUARTZ CRYSTAL MORPHOLOGY AND COMPOSITION OF FLUID INCLUSIONS AS INFERRED FROM FISSURES IN CENTRAL SLOVAKIA (CZECHOSLOVAKIA)

Abstract Fluid inclusion investigations on quartz from fissures have revealed several compositional types of fluids expelled at various stages of a low-grade metamorphism in Central Slovakia. Saturated brines with traces of methane leaked through migmatites and granitoids in the Nizke Tatry Mts. at temperatures of 360–375°C and pressures of 2.1–2.3 kbar, as calculated from K/Na ratios and homogenization temperatures of inclusion fluids. The earlier stage of low-grade metamorphism in the Slovenske Rudohorie Mts. showed highly saline fluids to circulate at temperatures of 420–495°C and pressures of 2.1–2.9 kbar. Indications for mixing CO 2 -rich moderately saline fluids with portions of highly saline CO 2 -poor fluids have occasionally been observed in quartz from fractures and sheared zones originated in the later stage of low-grade metamorphism. However, CO 2 -rich fluids are by far the most abundant compositional type expelled at this stage at temperatures probably within the range of 325–420°C. Morphology of quartz crystals on five localities change from simple to more complicated according to the increase of the K/Na ratio in fluids.