EN 14662-4:2005

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Method description
  4.1 Principle
  4.2 Reagents and materials
  4.3 Apparatus
  4.4 Sample tube conditioning
  4.5 Sampling
  4.6 Procedure
  4.7 Calculation of mass concentration of benzene
  4.8 Report
5 Determination of measurement uncertainty
  5.1 Introduction
  5.2 Parameters contributing to measurement uncertainty
6 Recommendations for use
Annex A (informative) Diffusive uptake rates for benzene on
                      sorbent tubes (without membrane)
Annex B (informative) Description of sorbent types
Annex C (informative) Guidance on sorbent selection
Annex D (informative) Guide on sorbent use
Annex E (informative) Assessment of performance indicators and
                      uncertainty contributions
Annex F (informative) Performance characteristics
Bibliography

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.