Quantitative colorimetric assays for methamphetamine

This chapter focuses on the colorimetric assays for quantitative analysis of methamphetamine. Marquis and Simon's tests are commonly used for indicating the presence or absence of methamphetamine in a suspected sample. An orange–brown product from a Marquis test indicates the possible presence of methamphetamine and/or amphetamine and a blue product from the Simon's test indicates the possible presence of a secondary amine including methamphetamine. Both colorimetric assays can be used as qualitative analysis and a spectrophotometric method is commonly required for quantification. Digital image analysis has been reported for quantitative colorimetric testing of substances such as methamphetamine through a method using digital image colorimetry. The results from digital image colorimetry revealed a very good correlation with data acquired from accurate instrumental analysis of the same sample. Digital image colorimetry provides great potential value in the development of rapid, simple, portable, and inexpensive colorimetric assays which have the potential deliver quantitative analysis