Cilësia e ajrit të mjedisit – Metoda standarde për matjen e përqëndrimeve të benzenit Pjesa 5 : Marrja e mostrës me difuzion e pasuar me desorbim në tretës dhe gazkromatografi.

Ambient air quality - Standard method for measurement of benzene concentrations - Part 5: Diffusive sampling followed by solvent desorption and gas chromatography

Asnjë informacion i shtuar.

This part of EN 14662 is in accordance with the generic methodology selected as the basis of the European Union reference method for the determination of benzene in ambient air [1] for the purpose of comparison of measurement results with limit values with a one-year reference period. This part of EN 14662 gives general guidance for the sampling and analysis of benzene in air, by diffusive sampling, solvent desorption and capillary gas chromatography. This part of EN 14662 is valid for the measurement of benzene in a concentration range of approximately 0,5 mg/m3 to 50 mg/m3 in an air sample typically collected over a period of several days or several weeks. A number of devices are recommended for the sampling of benzene, each device having a different range of applicability, particularly with regard to the optimum period of exposure. The upper limit of the useful range is set by the sorptive capacity of the activated charcoal and, subject to dilution of the analysed solution, by the linear dynamic range of the gas chromatograph column and detector or by the sample splitting capability of the analytical instrumentation used. The lower limit of the useful range depends on the noise level of the detector and on blank levels of benzene and/or interfering artefacts on the sampling devices or in the carbon disulphide. Alternative sorbents to activated charcoal may be used provided that the equivalence in performance characteristics of the procedure is demonstrated. Alternative desorption solvents to carbon disulphide may be used provided that the equivalence in performance characteristics of the procedure is demonstrated.