This Technical Practice Update (TPU) discusses the types and development direction of analytical methods and technologies used to identify and quantify these materials and impart a general understanding of how to interpret the quality of reported information. This TPU includes the following sections: Background, Relevance of Issue, What Has Been Done and What We Know, Sampling, Sampling Extraction Techniques, Analyses - Instrumentation and Methods, Instrumental Technique Summaries, Total Organic Carbon, Gas Chromatography/Electron Capture Detection, Gas Chromatography/Mass Spectrometry, Liquid Chromatography/Mass Spectrometry, High-Resolution Mass Spectrometers, Isotope Dilution Mass Spectrometry, Screening Methods, Toxicology/Toxicity Methods, Quality Control/Quality Assurance for the Analysis of Microconstituents, Where We Are Headed/Next Steps, References, and Appendix - List of the Most Frequently Discussed Microconstituents. Published by WEF. 2007. Electronic download. 45 pages.