Small volume liquid extraction of amphetamines in saliva

Molecularly imprinted polymers as a selective sorbent for forensic applications in biological samples-a review

Molecularly imprinted polymers (MIP) consist of a molecular recognition technology with applicability in different areas, including forensic chemistry. Among the forensic applications, the use of MIP in biological fluid analysis has gained prominence. Biological fluids are complex samples that generally require a pre-treatment to eliminate interfering agents to improve the results of the analyses. In this review, we address the development of this molecular imprinting technology over the years, highlighting the forensic applications of molecularly imprinted polymers in biological sample preparation for analysis of stimulant drugs such as cocaine, amphetamines, and nicotine.

A simplified fabric phase sorptive extraction method for the determination of amphetamine drugs in water samples using liquid chromatography-mass spectrometry

Fabric phase sorptive extraction (FPSE) can directly extract the target analytes and simultaneously determine many similar substances from complicated sample matrices. Also, it has very high chemical stability. Therefore, we used fabric phase sorptive extraction to analyze three amphetamine drugs (amphetamine (AM), methamphetamine (MAM), and 3,4-methylenedioxymethamphetamine (MDMA)) in water. This was coupled with ultrahigh-performance liquid chromatography and tandem mass spectrometry. The effects of different sorbent chemistries such as sorption time, ratios of back-extraction solvents, back-extraction time, and the salt effect on the extraction efficiency were studied; the optimum operation conditions were determined. Medium polarity polar polymer-coated FPSE media were created using short-chain poly (tetrahydrofuran) (PTHF). This is the most efficient extraction media for the analytes of interest. Under the optimized conditions, the linear range of the three amphetamine drugs were 0.1–150.0 (AM, MAM) and 0.5–200 ng mL⁻¹ (MDMA). The correlation coefficients (γ) were 0.9947 (AM), 0.9925 (MAM), and 0.9918 (MDMA). The detection limits (LOD) were 0.025 ng mL⁻¹ for AM, 0.029 ng mL⁻¹ for MAM, and 0.01 ng mL⁻¹ for MDMA. The corresponding limit of quantification values (LOQ) were 0.083 ng mL⁻¹, 0.097 ng mL⁻¹, and 0.031 ng mL⁻¹, respectively. The recoveries were 73.4–91.6%, 82.6–95.4%, and 92.7–95.3%, respectively, and the relative standard deviations (RSD) were 1.65–6.88%, 1.38–6.11%, and 1.58–7.34%, respectively. Moreover, our method can be successfully applied for the analysis of amphetamines in wastewater samples, and at the same time, lays the foundation for the future detection of such substances.

Fabric phase sorptive extraction (FPSE) can directly extract the target analytes and simultaneously determine many similar substances from complicated sample matrices.

Development of microextraction by packed sorbent for toxicological analysis of tricyclic antidepressant drugs in human oral fluid

The aim of this study was to apply microextraction by packed sorbent (MEPS) to the isolation of six tricyclic antidepressants (TCADs): nordoxepin, doxepin, desipramine, nortriptyline, imipramine, and amitriptyline from human oral fluid. Samples were collected from healthy volunteers via free spillage from the oral cavity to disposable test tubes. A method of oral fluid sample pretreatment was developed and optimized in terms of suitability for MEPS extraction and removing of interfering agents (protein, food debris, or air bubbles). Moreover, it was short and simple to perform with limited sample consumption (150μL). Extracts were analysed by UHPLC-MS. The MEPS/UHPLC-MS method was validated at three concentration levels (2.00, 4.00 and 8.00ng/mL) of all analytes in the range 1.25-10.0ng/mL. The following parameters were determined: limit of detection, limit of quantification, precision, and accuracy. For all tested concentration levels, the intra- and inter-day repeatability did not exceeded 8.1% and 12.2%, respectively. Gained LOQ value, 0.50ng/mL, made the MEPS/UHPLC-MS method to be a useful tool in clinical and forensic laboratories, which was demonstrated on the basis of analysis of real samples.

Stir-membrane liquid microextraction for the determination of paracetamol in human saliva samples

Background: In this article, stir-membrane liquid microextraction is adapted for the analysis of volume-limited biological samples, using as a model analytical problem the determination of paracetamol in human saliva by LC with UV. A three-phase microextraction mode is used for the extraction of the target analyte, taking advantage of its acid–base properties. Results: All the variables involved in the extraction have been studied and optimized in depth. The method has been analytically characterized on the basis of its linearity, sensitivity and precision. The LOD is 0.5 µg/l while the repeatability, expressed as RSD, is better than 14.2 %. A tenfold preconcentration factor was obtained, which involves an absolute recovery value of 25%. Moreover, the relative recovery is very close to the 100%. Conclusion: Finally, the proposed method has been used to perform a PK study of paracetamol.

Rapid screening and determination of designer drugs in saliva by a nib-assisted paper spray-mass spectrometry and separation technique

A method for the rapid screening and determination of amphetamine-type designer drugs in saliva by a novel nib-assisted paper spray-mass spectrometry procedure is described. Under optimized conditions, the limit of detections for amphetamine derivatives (model samples: o-, m-, p-chloroamphetamine and o-, m-, p-fluoroamphetamine, respectively) were determined to 0.1 μg/mL by the nib-assisted paper spray-mass spectrometry method. This method is easier and has a higher sensitivity than similar methodologies, including atmospheric pressure/matrix-assisted laser desorption ionization mass spectrometry and electrospray-assisted laser desorption ionization/mass spectrometry. Data obtained using more classical separation methods, including liquid chromatography and capillary electrophoresis, are also reported.

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.