Search PubMed⌕ Search

Biomedical subjects

J Krajewski

Publications and source records attributed to J Krajewski.

At least 73 records · Page 4Linked to original sources
PubMed1978

[Determination of vinyl chloride in the air by the gas chromatography method].

The purpose of the paper was to work out a gas chromatographic method for determination of vinyl chloride in the air at work places in the chemical plants. The best results have been obtained at 50 degrees C on 3-meter column containing 10% SE-30 on Chromosorb W AW DMCS, 80--100 mesh. Two methods of sampling have been considered: that of collecting samples in vacuum pipettes and that of adsorption on charcoal. In the former method stability of collected samples has been investigated (Fig. 3). A slight decrease in concentration of the vinyl chloride (approximately 3%) was found in four hours. In the latter method two ways of determination of vinyl chloride desorption coefficient from charcoal have been investigated. Since no essential difference in values of desorption coefficient has been observed, both ways for determination of desorption coefficient may be employed. A modified device for preparation of standard concentrations of vinyl chloride in the air has been utilized in our research (Fig. 2). The relative standard deviation resulting from analysis of samples was +/- 0.075. The minimum determinable amount of vinyl chloride was found to be 10 ng per injection.

Air↗
PubMed1977

[Gas chromatographic method for the determination of P-chlorphenol in the air].

The gas chromatographic method for determination of p-chlorophenol in the air in presence of phenol has been elaborated. A good separation of investigated compounds was achieved using 10% FFAP on Chromosorb W as a stationary phase. Air was sampled to water solution of sodium carbonate. The method enables determination of 0.25 mg/m3 of p-chlorophenol, and 2.5 mg/m3 of phenol at the air sample volume 10 dm3.

Air↗
PubMed1977

[Methods of gas mixture preparation].

State methods for preparation of gas mixtures have many disadvantages. Losses of components due to adsorbtion on the container surface (glass of plastic) are the main problem. Flow--dilution dynamic systems are much more convenient, giving practically unlimited quantities of mixtures of chemical substances with air at fixed concentration. Dynamic methods enable rapid change in concentration of generated mixture and surface adsorbtion does not exist. To produce at stable rate the substance to be diluted with air, microdiffusion, motor driven syringes (or peristaltic pumps) saturated vapours, permeation tubes and pressure cylinders may be employed. Our experience showed that pressure cylinders are the best for preparation of mixtures of gases (i.e. vinyl chloride) with air and peristaltic pumps are the best as the source of vapours for further dilution. The latter method may be employed as well for mixtures of several compounds (i.e. acetic acid esters) with air.

Chemistry Techniques, Analytical↗
PubMed1977

[Gas chromatography determination of trichloroethylene and tetrachloroethylene in the air].

Parameters of gas chromatographic separation and determination of trichloroethylene and tetrachlorethylene have been elaborated. The best separation has been achieved on column containing 7% OV-17 on Chromosorb W AW DMCS. For air samples collection, a method of absorption on charcoal and consequent desorption with carbon disulfide has been adapted. Stability of concentration of determined compounds in gas pipettes has been also evaluated. The investigations proved the concentration of compounds in gas pipettes to decrease in time. The magnitude of decrease was dependent on initial concentration and the boiling points of the compounds.

Air Pollutants↗