Effect of Four Laboratory Decontamination Procedures on the Quantitative Determination of Cocaine and Metabolites in Hair by HPLC-MS

Abstract

The testing for drugs of abuse in hair is increasingly used to detect illicit substances. Laboratories have implemented various decontamination, or washing, procedures in order to eliminate concerns regarding potential contamination of the hair with drug from the environment. However, the effect of these decontamination procedures on drug incorporated into the hair shaft via systemic exposure is unknown. This study evaluated the effect of four simple laboratory wash procedures on the quantitative measurement of cocaine and its metabolites in hair from rats administered cocaine by intraperitoneal injection. Washes included (1) methanol only; (2) 0.1 M phosphate buffer, pH 6.0; (3) 0.1 M phosphate buffer, pH 8.0; and (4) isopropanol and phosphate buffer, pH 5.5. Cocaine and its major metabolites, benzoylecgonine, norcocaine, ecgonine methyl ester, and cocaethylene, were analyzed using high-performance liquid chromatography coupled to atmospheric pressure electrospray ionization mass spectrometry. All four washes resulted in significant differences from unwashed hair controls (p < or = 0.05) for some or all of the detectable analytes. Because different wash procedures lead to significant differences in the measured concentrations of analytes in hair known to contain drug, quantitative data must be interpreted cautiously based on the wash procedures employed.

Wool cortisol is a better indicator of stress than blood cortisol in ewes exposed to heat stress and water restriction

“…1-3002, State College, Pennsylvania, USA). Washing procedure using isopropanol and methanol was performed as described by Davenport et al (2006) followed by drying (Paulsen et al, 2001). The dried wool samples were reduced to fine particles using scissors.…”

“…Samples were then gently mixed on a rotator at room temperature for 3 min per wash, and 2 ml of the solvent from each wash was collected in a separate tube to determine the concentration of overall cortisol lost during the washing procedure and mentioned as washed wool cortisol. The wool samples were then allowed to dry for 7 days in a clean protected hood (Paulsen et al, 2001). After drying, ∼50 mg of finely reduced wool samples (by scissors) was weighed and placed into a 2 ml microcentrifuge tube.…”

Morphological changes in human head hair subjected to various drug testing decontamination strategies

“…However, significant questions remain about hair testing and the potential for external contamination to result in false positive interpretations of the analytical results. Concerns about external contamination have led to the use of various decontamination protocols for the removal of drug that may be loosely associated with the hair as a result of deposition from the individual's surroundings rather than actual drug use [6,7].…”

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.…”