A validated GC-MS method for ketamine and norketamine and its use in authentic cases

Abstract

This work has shown that it is a valid method for determining ketamine, norketamine and amphetaminesderivates in hair samples of forensic cases. This method was validated meeting the criteria of sensitivityand accuracy for detecting repeated consumption of ketamine in hair samples of forensic interest,according to the proposed cut-off for ketamine of 0.5 ng/mg. The detection of norketamine alloweddiscriminating between active uses and external contamination. The assessed method was applied foranalyzing 1189 hair samples of judicial interest received in the INTCF along 15 months, obtaining 62positive in ketamine consumption. This means a 5.2% of positivity. Ketamine consumers present a profileof young age (21&-30 years old), polydrug use with consumption of synthetic substances preferablyMDMA and, then, amphetamine. As consumer is collective, prone to consume new psychoactivesubstances, requires special attention due to they show a consumer profile with higher prevalence inMDMA than amphetamine, indicating that ketamine consumers belong to a subgroup with a differentprofile within the INTCF casuistry.The results of the exercises of the proficiency tests performed satisfactorily in all cases. In conclusion, itis a suitable method also to evaluate the chronic consumption of ketamine, in addition to amphetaminesin the same method of analysis.