Division 2.3.7 Performance criteria and requirements for the determination of an analyte by GC in combination with electron capture detection (ECD)

An internal standard shall be used if a material suitable for this purpose is available. It shall preferably be a related substance with a retention time close to that of the analyte. The analyte shall elute at a retention time which is typical for the corresponding calibration standard under the same experimental conditions. The minimum acceptable retention time for an analyte shall be two times the retention time corresponding to the void volume of the column. The ratio of the retention time of the analyte to that of the internal standard, i.e. the relative retention time of the analyte, shall be the same as that of the calibration standard in the appropriate matrix, within a margin of ± 0,5 %. The nearest peak maximum in the chromatogram shall be separated from the designated analyte peak by at least one full peak width at 10 % of the maximum height of the analyte peak. For additional information, co-chromatography may be used.