ABSTRACT
Quality control activities are therefore the most important and essential tools to insure the reliability of analytical data. This chapter discusses some of the fundamental aspects of quality control studies. It discusses the basic principles and techniques of conventional Thin-Layer Chromatography (TLC) for pesticide-residue analysis. Degradation products are altered pesticide molecules resulting from "weathering" by chemical processes in the environment such as hydrolysis, photochemical action, and oxidation. Pesticide residue analysis is difficult and extremely complex because of the need to isolate, accurately identify, and measure such minute quantities in the presence of large amounts of extraneous materials. Because of the complexity of residue analysis, there are two major types of analytical uncertainties derived from them. They are: true identity of the contaminant; and real quantity of the contaminant analyzed.
