“Holding Time” can be defined as the maximum period between sampling and analysis before the occurrence of significant sample degradation. They are stipulated because of the recognition that chemical and physical characteristics may change during this period. However, sampling method, sample container, storage (conditions and preservative, as well as time), shipping conditions, etc, contribute to a collective effect on sample stability. This paper discusses the significance of holding time as a variable relative to method performance and suggests alternative preservation techniques.
As a result of the enactment of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) in 1980, and the subsequent delegation of its authority by the President of the United States to the Administrator of the Environmental Protection Agency, the Contract Laboratory Program (CLP) has been developed to analyze “Superfund” samples in a broad-based manner in order to obtain the most information about them with a reasonable investment in time and money. The CLP uses gas chromatography/mass spectrometry (GC/MS) as its primary tool for analysis of samples for organic constituents. More explicitly, it employs solvent extraction techniques respectively appropriate for water and soil/sediment matrices prior to MS detection for semi-volatile compounds. An elaborate Quality Assurance/Quality Control (QA/QC) system is in place to guarantee that data generated by the CLP is of known quality and will hold up to the rigors of litigation, in addition to providing an ongoing monitoring of CLP laboratories QA/QC data in order to guarantee their successful performance.
As a result of the enactment of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) in 1980, and the subsequent delegation of its Authority by the President of the United States to the Administrator of the Environmental Protection Agency, the Contract Laboratory Program (CLP) has been developed to analyze “Superfund” samples in a broad-based manner in order to obtain the most information about these samples with a reasonable investment in time and money. The CLP uses gas chromatography/mass spectrometry (GC/MS) as its primary tool for analysis of samples for organic constituents. More explicitly, it employs purge and trap techniques prior to MS detection for analysis of samples for volatile compounds. An elaborate Quality Assurance/Quality Control (QA/QC) system is in place to guarantee that data generated by the CLP is of known quality and will hold up to the rigors of litigation in addition to providing an ongoing monitoring of CLP laboratories QA/QC data in order to guarantee their successful performance.
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