New sorbents and indicator powders for preconcentration and determination of trace metals in liquid samples

Two approaches to immobilize complex-forming analytical reagents (PAN, PAR, Xylenol orange, Brombenzothiazo, Crystal violet, Cadion, and Sulfochlorophenolazorhodanine) for the preparation of new sorbents and indicator powders are suggested: on-line coating of reversed-phase silica gel by reagents or doping of porous sol-gel silica with reagents. The retention of Ag, Cd, Cu(II), Co(II), Fe(III), Mn(II), Ni, Pb, and Zn on the sorbents developed was investigated. Quantitative sorption and desorption conditions were optimized. Procedures for the determination of Cd, Cu(II), Fe(III), Pb, and Zn with flame atomic absorption, spectrophotometric, and diffusion scattering spectrometric detection were elaborated. Detection limits for Cd, Cu(II), Fe(III), Pb, and Zn were 3 μg/L, 6 μg/L, 5 μg/L, 40 μg/L, and 1 μg/L, respectively. The procedures were used for the analysis of various real samples, e.g., natural and waste waters, and food. Received: 17 July 1997 / Revised: 20 January 1998 / Accepted: 5 February 1998     

Xerogels doped with 1-(2-pyridylazo)-2-naphthol and Xylenol Orange: Indicator tubes and indicator powders for determining copper(II) and iron(III) in solution

Silica-based xerogels doped with l-(2-pyrilylazo)-2-naphthol and Xylenol Orange were prepared. The xerogels differ in the specific surface and the reagent concentration. Modified xerogels were used as indicator powders for determining copper(II) and iron(III) using indicator tubes. The effects of the reagent concentration in the indicator powder and its specific surface on the length of the colored zone were studied. Indicator tubes were developed for determining 0.3–300.0 mg/L copper(II) and 1.0–120.0 mg/L iron(III) in solutions. The results of determining copper(II) in plant mineral food and iron(III) in natural waters and ashed milk powder are presented.     

Chemical analysis and medicine

The main directions in using chemical analysis in medicine are considered, such as diagnosis of diseases, sanitation and hygiene control, doping control, direct identification of microorganisms, DNA-analysis, etc.     

Microstructure of Si Crystals Subjected to Irradiation with High-Energy H+ Ions and Heat Treatment by High-Resolution Three-Crystal X-Ray Diffraction and Transmission Electron Microscopy

Physics of the Solid State - The structural features of the formation of radiation defects in proton-implanted layers of silicon plates during their heat treatment have been studied. New data on...     

Approximation of the electric field of conductors by screened point charges and multipoles

Efficiency of application of the mathematical screened multipole apparatus for a variational solution of the problem on screened conductor capacitance is demonstrated. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 35–41, January, 2007.     

Solvent extraction-electrothermal atomic-absorption analysis

The review discusses the problems of rational combination of solvent-extraction separation and preconcentration of trace elements with their determination by electrothermal atomic-absorption spectrometry.