Forensic Science International: Reports (Dec 2020)
Stability of seized amphetamine during 32 months of storage
Abstract
The designated organisation to report on narcotic and psychotropic substances from illicit traffic is the Government Delegations distributed throughout the territory of Spain. Within its Health and Social Policy Area, there are specific laboratories responsible for preparing these expert reports. These reports certify both the identity and purity of the controlled substance and are crucial for judicial organisations to set penalties, which vary according to the purity of the seized material.Occasionally after the initial expert report included in the judicial instruction period, the judges require a re-analysis, and often the new results have different concentration from the first.This study aims to make predictable the impact that storage time has on the purity of the controlled substance to explain how two analysis developed on the same material at different times may not bring about the same result.Three different variables were measured: storage time, storage conditions (temperature and humidity), and the initial purity of the sample. The controlled substance chosen to carry out the study was amphetamine.Samples of seized substances with different degrees of purity were subdivided and stored under two different storage conditions: “E”- Environmental (temperature of 22,14° and humidity of 66,36 %) and “R”-Refrigerated (temperature of 4,7 °C and humidity of 28,29 %). Samples were analyzed at the 12th, 24th, and 32nd month.An ANOVA study of data found that the only variable which affected the purity of amphetamine was storage time, having set up a threshold for statistical significance in p < 0,05. Neither storage conditions nor original purity of the sample had any effect.It was observed a loss of purity during the storage time of 1,59 % at 12 months, 2,34 % at 24th months, and 6,43 % at 32 months. The percentual change found at 12 months and 24 months cannot be said to be a significant result since it is within the error rate associated, according to the Horwitz equation (2%), and the estimated error of the technique (5%).
