1.1 This Recommendation provides the procedures for testing and verifying the performance of a gas chromatograph (GC) system when used for the measurement of pesticides and other toxic substances in carrying out pollution control programs and in assessing the quality of food products as mandated by national laws and regulations. It does not intend to exclude any equivalent means of measurement or analysis for such toxic substances. 1.2 The GC systems covered in this Recommendation are intended to be used in a fixed or mobile laboratory under controlled ambient conditions. Portable GCs for field applications are covered in OIML R 113. GCs coupled with other analytical instruments such as GC-mass spectrometers and GC-Fourier transform infrared spectrometers are also not covered in this Recommendation. 1.3 Instrument performance better than the criteria specified in this Recommendation may be accomplished by optimizing the performance of major components of the measurement system. In such cases, success may depend on the knowledge, skill, and experience of the operator. 1.4 A sample usually requires undergoing a specific preparation technique prior to an analysis with a GC system. Sampling techniques and methods of analysis are beyond the scope of this Recommendation. 1.5 This Recommendation does not address requirements and tests that may be necessary for operator safety. Therefore, users should determine whether instruments meet the safety and labeling requirements specified in national regulations.