Ami acid analysis is a technique that has become commonplace in biotechlogy, biomedical, and food analysis laboratories. This book describes a variety of ami acid analysis techniques and how each technique can be used to answer specific biological questions. The first two chapters in Ami Acid Analysis Protocols introduce the concepts, basic theory, and practice of ami acid analysis. The following chapters give detailed instructions on various methods and their applications. As highlighted, there are many different approaches to ami acid ana- sis, but in all cases the results depend heavily on the quality of the sample. Therefore a new way to desalt samples prior to hydrolysis is covered as an introductory chapter (Chapter 3), and most authors have devoted a section to sample preparation, especially to the collection and storage of bodily fluids. Some of the ami acid analysis methods described in this book are based on HPLC separation and analysis after precolumn derivatization. The precolumn derivatization techniques described use (a) 6-amiquilyl-N-hydro- succinimidyl carbamate (AQC) (Chapters 4 and 8); (b) 1-fluoro-2- dinitrophenyl-5-L-alanine amide (Marfey's reagent), which allows sepa- tion and analysis of enantiomeric ami acids (Chapter 5); (c) O-phthalal- hyde (OPA) (Chapters 6 and 10); (d) butylisothiocyanate (BITC) and benzylisothiocyante (BZITC) (Chapter 11); (e) phenylisothiocyanate (PITC) (Chapters 12 and 13); (f) ammonium-7-fluorobenzo-2-oxa-1,3-diazole-4-s- fonate (SBD-F) (Chapter 17); and (g) 9-fluorenylmethyl-chloroformate (FMOC-Cl) (Chapter 10).