Field drug testing kits are widely used by law enforcement agencies around the country as a presumptive test for the identification of illicit substances. The modified Scott test is one such test that is supposed to detect the presence of cocaine. There has been controversy over this test and others like it since it has been reported that there are common household and over-the-counter substances that result in a false positive identification of cocaine. Through this research, we have determined that diphenhydramine HCl and lidocaine produce false positive results. There are various factors that affect the false positive result such as load, mixing time, and temperature. These variables were studied as well as the nature of the complex formed between these substances and the cobalt thiocyanate that is used in the test using UV-VIS spectroscopy. This research is meant to explain further some of the inconsistencies found in similar previous studies and suggest possible alternatives to this test using safer and greener chemicals than the cobalt thiocyanate, concentrated hydrochloric acid, and chloroform that are commonly used.

Factors influencing the modified Scott test for cocaine using substances that result in a false positive

2019 Spring National Meeting

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