MCU14/0056 Response to SARA - Consulting Report

EN 858-1:2002 (E)

A.3.6 Example GC conditions
— Injection technique: ° Programmed temperature vaporisation (PTV)
— Injection temperature: 50 °C to 300 °C
— Injection volume: 1 LI (NOTE Larger volumes will give increased sensitivity)
*“— Column length: 30m
— Column internal diameter: 0,25 mm
— Liquid phase: DB 5 MS
— _ Pre-column: Deactivated fused silica capillary
— Carrier gas: Hydrogen (Hz)
— Carrier gas pressure: ~ 80 kPa

— Oven temperature programme: 40 °C for 5 min, 10 °C/min to 300 °C for 20 min

— Detector: Flame ionisation detector (FID)
— Detector temperature: 300 °C

— Make up gas: Nitrogen (Na)

— Make up gas flow: 25 ml

The system shall be able to integrate the whole chromatogram and compensate for the blank chromatogram.

The total peak area between n-decane and n-tetracontane shall be integrated. The integration begins immediately
at the end of the n-decane peak and ends immediately in front of the n-tetracontane peak. The signal level before
the solvent peak shall-be used as the baseline. The total peak area for the sample is measured and the area for a
blank chromatogram (spiked petroleum ether) is subtracted. This correction eliminates the effect of column
bleeding. The extract may be diluted to bring it within the calibration range. A blank chromatogram shall be run at
least once every ten samples. A check on the validity of the calibration shall be done with each series of samples
using an oil in petroleum ether standard with a concentration between 40 % and 80 % of the calibration range. The
result of the check solution shall be within 10 % of the calibration.

A.3.7 Calibration
The system shall be calibrated using a series of five external standards covering the required analysis range and a

blank. These standards are prepared in petroleum ether spiked with n-decane and n- tetracontane. The standards
shall be prepared by dilution of a stock standard (see Tables A.1 and A.2).

38 This is a licensed reproduction produced by SAI Global Lid, an authorized distributor of British Standards