1.1 This practice covers requirements for defining, testing, and verifying the performance of high performance liquid chromatographic (HPLC) systems when used for trace analysis of pesticides and toxic substancesin carrying out pollution control programs and in assessing the quality of food products as mandated by national laws and regulations. As a practical matter, this practice is intended to cover requirements of reversed-phase (adsorption) HPLC systems. Microbore column and ion-exchange column HPLC systems are not covered here. It is not intended to exclude any other equivalent means of analysis. An HPLC system can successfully be applied in the analysis of a variety of sample types including ground and surface water, municipal and industrial effluents, workplace air, soils and sediments, plant abd animal tissue, and food products. Collection and extraction techniques , appropriate to the sample type, are required prior to analysis. Sampling techniques and measurement methods are not covered in this recommendation; however, some relevant measurement methods may be found in references listed in Appendix X1.