Levels of cocaine and its metabolites in washed hair of demonstrated cocaine users and workplace subjects

Distribution of 6-monoacetylmorphine and morphine in head and pubic hair from heroin-related deaths

“…However, other studies have reported that positive heroin ingestion can be demonstrated with metabolite-to-parent drug ratio outside this recommended limit. The authors of these studies recommended that the results with the ratio outside the threshold should be carefully judged with other criteria and the ratio should not be a single decisive factor [1,13,17,18]. They also suggested that the ratio should be modified according to the specific analytical method because morphine can be produced from 6-AM by chemical degradation [1].…”

Removing and identifying drug contamination in the analysis of human hair

“…The wash procedure and application of the wash criterion (which essentially provides the additional safeguard of mathematically estimating the effect of further washing) identified all contaminated samples correctly. This wash methodology has also been tested with hair from subjects demonstrated to be drug users by one or more drug-positive urines [7][8][9].…”

New trends in hair analysis and scientific demands on validation and technical notes

“…Recently, Romano et al demonstrated the problem that even using sophisticated decontamination procedures it was not possible to distinguish a drug-contaminated subject from an active user after a single external contamination with small amounts of drugs [42,43]. A lot of strategies were recently tested [44][45][46][47][48][49][50], however, there exists no consensus about an optimal decontamination procedure and it has to be considered individually whether a washing using different solvents is sufficient or already leads to an untimely extraction of incorporated analytes. It has to be taken into account that a decontamination procedure can affect the extraction efficiency of incorporated drugs and has to be considered in the interpretation of quantitative results.…”