CEN/TC 264/WG 13 - Reference method for determination of benzene in ambient air

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.

This part of EN 14662 is in accordance with the generic methodology 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 pumped 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 µg/m3  to 50 mg/m3 in an air sample of 1 m3 volume, typically collected over a period of 24 hours.
The upper limit of the useful range is set by the sorptive capacity of the sorbent and 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 sorbent and in the desorption solvent.
The method described here is based on sampling on sample tubes typically containing 100 mg of activated charcoal and desorption using 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.

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, thermal 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 14 days.
The upper limit of the useful range is set by the sorptive capacity of the sorbent and 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 sorbent. Artefacts are typically sub ng for sorbents such as graphitised carbon, but higher levels of aromatic hydrocarbons have been noted in other sorbents.

This part of EN 14662 gives general guidance for the sampling and analysis of benzene in air by pumped sampling, thermal desorption and capillary gas chromatography.
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 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 24 hours.
The upper limit of the useful range is set by the sorptive capacity of the sorbent and by the linear dynamic range of the gas chromatograph column and detector or by the sample splitting capacity 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 sorbent. Artefacts are typically sub ng for sorbents, but  higher levels of aromatic hydrocarbons have been noted in other sorbents. The detection limit will be approximately 1/10 of the lower concentration range.

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.
The standard describes guidelines for measurements with, and type approval of, automated gas chromatographs. The use of automated instruments gives this part a different structure compared to the other parts including the procedure for selecting an appropriate automated gas chromatograph by means of type approval tests.
Requirements for use in the field are also described.
The standard is applicable to measurements of airborne benzene vapour in the concentration range from 0 µg/m3 to 50 µg/m3 (Standardised to 101,3 kPa and 293 K). This concentration range represents the certification range for benzene in the type approval test.