Microextraction by Packed Sorbent as a Novel Strategy for Sample Clean-Up in the Determination of Methadone and EDDP in Hair

A microextraction by packed sorbent (MEPS) procedure for rapid concentration of methadone and its primary metabolite (EDDP) in hair samples was developed. The miniaturized approach coupled to gas chromatography with tandem mass spectrometry (GC-MS-MS) was successfully validated. Hair samples (50 mg) were incubated with 1 mL of 1 M sodium hydroxide for 45 min at 50°C, time after which the extract was neutralized by adding 100 μL of 20% formic acid. Subsequently, MEPS was applied using a M1 sorbent (4 mg; 80% C8 and 20% strong cation-exchange (SCX)), first conditioned with three 250-μL cycles of methanol and three 250-μL cycles of 2% formic acid. The extract load occurred with nine 150-μL cycles followed by a washing step involving three 50-μL cycles with 3.36% formic acid. For the elution of the analytes, six 100-μL cycles of 2.36% ammonium hydroxide in methanol were applied. The method was linear from 0.01 to 5 ng/mg, for both compounds, presenting determination coefficients greater than 0.99. Precision and accuracy were in accordance with the statements of international guidelines for method validation. This new miniaturized approach allowed obtaining recoveries ranging from 73 to 109% for methadone and 84 to 110% for EDDP, proving to be an excellent alternative to classic approaches, as well as other miniaturized procedures.

Hair as an alternative matrix in bioanalysis

Alternative matrices are steadily gaining recognition as biological samples for toxicological analyses. Hair presents many advantages over traditional matrices, such as urine and blood, since it provides retrospective information regarding drug exposure, can distinguish between chronic and acute or recent drug use by segmental analysis, is easy to obtain, and has considerable stability for long periods of time. For this reason, it has been employed in a wide variety of contexts, namely to evaluate workplace drug exposure, drug-facilitated sexual assault, pre-natal drug exposure, anti-doping control, pharmacological monitoring and alcohol abuse. In this article, issues concerning hair structure, collection, storage and analysis are reviewed. The mechanisms of drug incorporation into hair are briefly discussed. Analytical techniques for simultaneous drug quantification in hair are addressed. Finally, representative examples of drug quantification using hair are summarized, emphasizing its potentialities and limitations as an alternative biological matrix for toxicological analyses.

A critical review of microextraction by packed sorbent as a sample preparation approach in drug bioanalysis

Sample preparation is widely accepted as the most labor-intensive and error-prone part of the bioanalytical process. The recent advances in this field have been focused on the miniaturization and integration of sample preparation online with analytical instrumentation, in order to reduce laboratory workload and increase analytical performance. From this perspective, microextraction by packed sorbent (MEPS) has emerged in the last few years as a powerful sample preparation approach suitable to be easily automated with liquid and gas chromatographic systems applied in a variety of bioanalytical areas (pharmaceutical, clinical, toxicological, environmental and food research). This paper aims to provide an overview and a critical discussion of recent bioanalytical methods reported in literature based on MEPS, with special emphasis on those developed for the quantification of therapeutic drugs and/or metabolites in biological samples. The advantages and some limitations of MEPS, as well as its comparison with other extraction techniques, are also addressed herein.

Novel strategies for sample preparation in forensic toxicology

This paper provides a review of novel strategies for sample preparation in forensic toxicology. The review initially outlines the principle of each technique, followed by sections addressing each class of abused drugs separately. The novel strategies currently reviewed focus on the preparation of various biological samples for the subsequent determination of opiates, benzodiazepines, amphetamines, cocaine, hallucinogens, tricyclic antidepressants, antipsychotics and cannabinoids. According to our experience, these analytes are the most frequently responsible for intoxications in Greece. The applications of techniques such as disposable pipette extraction, microextraction by packed sorbent, matrix solid-phase dispersion, solid-phase microextraction, polymer monolith microextraction, stir bar sorptive extraction and others, which are rapidly gaining acceptance in the field of toxicology, are currently reviewed.

Bioanalytical procedures and recent developments in the determination of opiates/opioids in human biological samples

The use and abuse of illegal drugs affects all modern societies, and therefore the assessment of drug exposure is an important task that needs to be accomplished. For this reason, the reliable determination of these drugs and their metabolites in biological specimens is an issue of utmost relevance for both clinical and forensic toxicology laboratories in their fields of expertise, including in utero drug exposure, driving under the influence of drugs and drug use in workplace scenarios. Most of the confirmatory analyses for abused drugs in biological samples are performed by gas chromatographic-mass spectrometric methods, but use of the more recent and sensitive liquid chromatography-(tandem) mass spectrometry technology is increasing dramatically. This article reviews recently published articles that describe procedures for the detection of opiates in the most commonly used human biological matrices, blood and urine, and also in unconventional ones, e.g. oral fluid, hair, and meconium. Special attention will be paid to sample preparation and chromatographic analysis.