Joseph Sherma is the John D. and Frances H. Larkin Professor Emeritus of Chemistry at Lafayette College, Easton, Pennsylvania. Professor Sherma has taught courses in analytical chemistry for more than 40 years, was head of the chemistry department for 12 years, and continues to supervise research students at Lafayette College. He is author and coauthor of over 600 papers and the author, coauthor, editor, and coeditor of over 60 books and manuals in the areas of analytical chemistry and chromatography.
Professor Sherma recently authored the article, "Thin Layer Chromatographic Analysis of Counterfeit Drugs" - which is featured in the Encyclopedia of Chromatography, Second Edition.
Here's a look at the Abstract:
Economical and reliable thin layer chromatographic (TLC) methods for rapid screening of counterfeit drugs that can be carried out by analysts in the laboratory or in the field by inspectors with limited analytical expertise using portable kits, with standard reference tablets to eliminate weighing, are described. Separations are performed on silica gel layers containing fluorescent indicator; separated spots are detected under ultraviolet lamps and with iodine detection reagent. Development and iodine detection are carried out in polyethylene bags, glass jars, or closed TLC tanks. Sample spots are compared with reference standards developed on the same layer to identify the ingredients and determine if their content is within the specification range.