Automated headspace solid-phase dynamic extraction for the determination of amphetamines and synthetic designer drugs in hair samples

Improving greenness and sustainability of standard analytical methods by microextraction techniques: A critical review

Since environmental awareness has increased in analytical chemistry, the demand for green sample preparation methods continues to grow. Microextractions such as solid-phase microextraction (SPME) and liquid-phase microextraction (LPME) miniaturize the pre-concentration step and are a more sustainable alternative to conventional large-scale extractions. However, the integration of microextractions in standard and routine analysis methods is rare, although these applications are used most frequently and have a role model function. Therefore, it is important to highlight that microextractions are capable to replace large-scale extractions in standard and routine methods. This review discusses the greenness, benefits, and drawbacks of the most common LPME and SPME variants compatible with gas chromatography based on the following key evaluation principles: Automation, solvent consumption, hazards, reusability, energy consumption, time efficiency, and handling. Furthermore, the need to integrate microextractions into standard and routine analytical methods is presented by using method greenness evaluation metrics AGREE, AGREEprep, and GAPI applied to USEPA methods and their replacements.

Advanced Solid-Phase Microextraction Techniques and Related Automation: A Review of Commercially Available Technologies

The solid-phase microextraction (SPME), invented by Pawliszyn in 1989, today has a renewed and growing use and interest in the scientific community with fourteen techniques currently available on the market. The miniaturization of traditional sample preparation devices fulfills the new request of an environmental friendly analytical chemistry. The recent upswing of these solid-phase microextraction technologies has brought new availability and range of robotic automation. The microextraction solutions propose today on the market can cover a wide variety of analytical fields and applications. This review reports on the state-of-the-art innovative solid-phase microextraction techniques, especially those used for chromatographic separation and mass-spectrometric detection, given the recent improvements in availability and range of automation techniques. The progressively implemented solid-phase microextraction techniques and related automated commercially available devices are classified and described to offer a valuable tool to summarize their potential combinations to face all the laboratories requirements in terms of analytical applications, robustness, sensitivity, and throughput.

Extraction of naturally occurring cannabinoids: an update

INTRODUCTION

Organic molecules that interact with the cannabinoid receptors are called cannabinoids, which can be endogenous, natural or synthetic compounds. They possess similar pharmacological properties as produced by the plant, Cannabis sativa L. Before cannabinoids can be analysed, they need to be extracted from the matrices.

OBJECTIVE

To review literature on the methods and protocols for the extraction of naturally occurring cannabinoids.

METHODOLOGY

An extensive literature search was performed incorporating several databases, notably, Web of Knowledge, PubMed and Google Scholar, and other relevant published materials. The keywords used in the search, in various combinations, with cannabinoids and extraction being present in all combinations, were Cannabis, hemp, cannabinoids, Cannabis sativa, marijuana, and extraction.

RESULTS

In addition to classical maceration with organic solvents, e.g. ethanol, pressurised solvent extraction, solvent heat reflux, Soxhlet extraction, supercritical fluid extraction, ultrasound-assisted extraction and microwave-assisted extraction, are routinely used nowadays for the extraction of cannabinoids from plant materials and cannabis consumer products. For the extraction of cannabinoids from biological samples, e.g. human blood, and also from food and beverages, and wastewater, solid-phase extraction and its variants, as well as liquid-liquid extraction are commonly used. Parameters for extraction can be optimised by response surface methodology or other mathematical modelling tools. There are at least six US patents on extraction of cannabinoids available to date.

CONCLUSIONS

Irrespective of the extraction method, extraction temperature, extraction time and extraction pressure play a vital role in overall yield of extraction. Solvent polarity can also be an important factor in some extraction methods.

Application of Microextraction-Based Techniques for Screening-Controlled Drugs in Forensic Context-A Review

The analysis of controlled drugs in forensic matrices, i.e., urine, blood, plasma, saliva, and hair, is one of the current hot topics in the clinical and toxicological context. The use of microextraction-based approaches has gained considerable notoriety, mainly due to the great simplicity, cost-benefit, and environmental sustainability. For this reason, the application of these innovative techniques has become more relevant than ever in programs for monitoring priority substances such as the main illicit drugs, e.g., opioids, stimulants, cannabinoids, hallucinogens, dissociative drugs, and related compounds. The present contribution aims to make a comprehensive review on the state-of-the art advantages and future trends on the application of microextraction-based techniques for screening-controlled drugs in the forensic context.

A dispersive solid phase extraction adsorbent based on aptamer modified chitosan nanofibers for zearalenone separation in corn, wheat, and beer samples

Highly selective separation of trace bio-toxins in food samples has long been a hot topic pursued by analytical chemists. In this paper, chitosan nanofibers prepared by freeze-drying were modified with aptamers for dispersive solid phase extraction (dSPE) of trace zearalenone. The morphology of achieved chitosan nanofibers was found to be uniform and continuous, and the length was at the micron level with about a 400 nm diameter. The immobilization capacity of the aptamer was as high as 10.1 μg on 5 mg chitosan nanofibers with good stability and repeatability, owing to the high specific surface area of nanofibers. The aptamer modified chitosan nanofibers (Apt-CNFs) showed specific selectivity to zearalenone with a selectivity coefficient of 2.65 compared to the scrambled oligonucleotide functionalized CNFs, and the selectivity factors over other analogs and reference compounds were from 1.57 to 50.0. After the optimization of extraction conditions, the Apt-CNF based dSPE was coupled with high-performance liquid chromatography for zearalenone monitoring, and a good linear range of 0.06-10.0 μg L-1 was achieved with a detection limit of 18.0 ng L-1. The spiking recoveries of 101-108%, 100-110%, and 98.3-101% were achieved for trace zearalenone in corn, wheat, and beer samples, respectively. The residual zearalenone was detected in corn and wheat with a content of 0.365 and 0.0775 μg g-1, respectively.

On-Line Sorbentless Cryogenic Needle Trap and GC–FID Method for the Extraction and Analysis of Trace Volatile Organic Compounds from Soil Samples

In this study, an automated sorbentless cryogenic needle trap device (ASCNTD) coupled with a gas chromatograph (GC) was developed with the aim of sampling, pre-concentration and determination of volatile organic compounds (VOCs) from soil sample. This paper describes optimization of relevant parameters, performance evaluation and an illustrative application of ASCNTD. The ASCNTD system consists of a 5 cm stainless steel needle passed through a hollow ceramic rod which is coiled with resistive nichrome wire. The set is placed in a PVC (Polyvinyl chloride) chamber through which liquid nitrogen can flow. The headspace components are circulated with a pump to pass through the needle, and this results in freeze-trapping of the VOCs on the inner surface of the needle. When extraction is completed, the analytes trapped in the inner wall of the needle were thermally desorbed and swept by the carrier gas into the GC capillary column. The parameters being effective on the extraction processes, namely headspace flow rate, the temperature and time of extraction and desorption were optimized and evaluated. The developed technique was compared to the headspace solid-phase microextraction method for the analysis of soil samples containing BTEX (Benzene, Toluene, Ethylbenzene and Xylene). The relative standard deviation values are below 8% and detection limits as low as 1.2 ng g−1 were obtained for BTEX by ASCNTD.

A Systematic Review of Solid-Phase Microextraction Applications in the Forensic Context

Since the introduction in 1990, the solid-phase microextraction (SPME) technology has brought significant progress in many fields of forensic sciences due to the versatility of this fast and solventless alternative to conventional extraction techniques. A systematic review about SPME applications in forensic context from January 1995 to June 2018 was carried out according to systematic review guidelines. The majority of the reviewed articles (40/133) aimed to identify drugs (cannabinoids, cocaine, opiates, amphetamines, simultaneous detection of different drugs of abuse, prescribed drugs); 29 of the 133 articles focused on the investigation of fatalities; 28 of the 133 papers used headspace SPME technique for the identification of markers of chronic alcohol abuse. Sixteen papers involved this technique for the isolation of volatile organic compounds for the human odor profile and 20 concerned forensic applications regarding living people. Solid-phase microextraction was preferably employed in the headspace mode and many kinds of fibers were employed, although polydimethylsiloxane was the most adaptable to many forensic realities. Gas chromatography/mass spectrometry was more frequently used, probably for the well-established coupling with SPME. Most of the papers validated their method to harmonize the scientific approaches of procedures development. Good outcomes are reported on biological material collected from living people as well as on cadaveric samples. The results obtained by most of the studies about alcohol biomarkers on scalp hair have been adopted by the "Society of Hair Testing" to demonstrate abstinence over a pre-defined time period and to assess chronic excessive alcohol consumption.

Green Approaches to Sample Preparation Based on Extraction Techniques

Preparing a sample for analysis is a crucial step of many analytical procedures. The goal of sample preparation is to provide a representative, homogenous sample that is free of interferences and compatible with the intended analytical method. Green approaches to sample preparation require that the consumption of hazardous organic solvents and energy be minimized or even eliminated in the analytical process. While no sample preparation is clearly the most environmentally friendly approach, complete elimination of this step is not always practical. In such cases, the extraction techniques which use low amounts of solvents or no solvents are considered ideal alternatives. This paper presents an overview of green extraction procedures and sample preparation methodologies, briefly introduces their theoretical principles, and describes the recent developments in food, pharmaceutical, environmental and bioanalytical chemistry applications.

Validation and application of hair analysis for the detection of methamphetamine in young Thai adults

Background: To date, blood and urine analyses have been the major methods of detecting methamphetamine (MA) use in Thailand. Recently, hair analysis has been introduced as an alternative and complementary procedure.

Objectives: To validate a simple, rapid, and economical method of analyzing hair for MA and its metabolite, amphetamine (AM).

Methods: The analysis employed solid-phase microextraction (SPME) coupled with gas chromatography and mass spectrometry (GC-MS). Simplicity, rapidity, and economy were achieved, in part, by optimizing SPME conditions and by eliminating deuterated reagents and the derivatization step in GC-MS. The validated method was employed to detect and quantify MA in 1,111 hair samples of young Thai research volunteers who reported using MA in the form of so-called “yaba” tablets at least 3 times during the previous 3 months.

Results: Validated data from the study indicated that the method’s linearity, accuracy, precision, limit of detection (LOD) and limit of quantitation (LOQ) met international standards for hair analysis of MA. Expressed as ng of MA per mg of hair (ng/mg), the LOQ was 0.5 ng/mg (102.39% accuracy, 5.46% precision). The method was less sensitive for quantification of AM in hair, with a LOQ of 2.5 ng/mg (103.41% accuracy, 6.95% precision). Using 0.5 ng/mg as a cutoff in the analysis of samples provided by admitted MA users, the study yielded an overall detection rate for MA of 35.5%, with a range of 0.51-54.61 ng/mg; the mean MA level was 4.90 ± 6.78 (±SD) ng/mg. Thirty-one percent of the participants reported they had consumed fewer than 10 yaba tablets during the previous 3 months. Of this group, 29% had hair samples that tested positive for MA. Detection rates trended upwards with increased yaba use. No relationship was found between the number of yaba tablets reportedly consumed and the concentration of MA detected in hair.

Conclusions: This study validated a rapid, simple, and economical SPME/GC-MS technique for quantification of MA in hair. The method was less sensitive for quantification of AM.

Optimization strategies of in-tube extraction (ITEX) methods

Microextraction techniques, especially dynamic techniques like in-tube extraction (ITEX), can require an extensive method optimization procedure. This work summarizes the experiences from several methods and gives recommendations for the setting of proper extraction conditions to minimize experimental effort. Therefore, the governing parameters of the extraction and injection stages are discussed. This includes the relative extraction efficiencies of 11 kinds of sorbent tubes, either commercially available or custom made, regarding 53 analytes from different classes of compounds. They cover aromatics, heterocyclic aromatics, halogenated hydrocarbons, fuel oxygenates, alcohols, esters, and aldehydes. The number of extraction strokes and the corresponding extraction flow, also in dependence of the expected analyte concentrations, are discussed as well as the interactions between sample and extraction phase temperature. The injection parameters cover two different injection methods. The first is intended for the analysis of highly volatile analytes and the second either for the analysis of lower volatile analytes or when the analytes can be re-focused by a cold trap. The desorption volume, the desorption temperature, and the desorption flow are compared, together with the suitability of both methods for analytes of varying volatilities. The results are summarized in a flow chart, which can be used to select favorable starting conditions for further method optimization.

Simultaneous quantification of multiple volatile active components in rat plasma using a headspace-solid phase dynamic extraction method coupled to gas chromatography-tandem mass spectroscopy: application in a pharmacokinetic study of Longhu Rendan pills

A HS-SPDE-GC-MS/MS method for investigating pharmacokinetics of l-menthol, borneol, isoborneol, and camphor in rat plasma after oral administration of LRPs.

In-sample derivatization-solid-phase microextraction of amphetamines and ecstasy related stimulants from water and urine

A solid-phase microextraction (SPME) method for the determination of five amphetamine type stimulants (ATSs) in water and urine samples is presented. Analytes were simultaneously derivatized with iso-butyl chloroformate (iBCF) in the aqueous sample while being extracted, improving in this way the extractability of ATSs and permitting their determination by gas chromatography-mass spectrometry (GC-MS). The SPME procedure was carefully optimized in order to achieve adequate limits of detection (LODs) for environmental concentrations. Hence, different operational parameters were considered: type of SPME coating, ionic strength, basic catalyzer and derivatizing agent amount, extraction time and temperature. The final SPME procedure consists into the extraction of 100mL of sample containing 2 g of dipotassium monohydrogen phosphate trihydrate and 100 μL of iBCF (1:1 in acetonitrile), for 40 min at 60°C with a polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber. Under these conditions, LODs in wastewater ranged from 0.4 to 2 ng L(-1), relative recoveries in the 84-114% range and relative standard deviations (RSD) lower than 15% were obtained. The application of the method to wastewater and river water samples showed the ecstasy ATS, 3,4-methylenedioxymethamphetamine (MDMA), as the most frequently detected, followed by methamphetamine, in concentrations around 20 ng L(-1). Finally, the method was downscaled and also validated with urine samples, proving its good performance with this matrix too: RSD<11%, recoveries in the 98-110% range and LODs lower than 0.1 μg L(-1).

Role of microextraction sampling procedures in forensic toxicology

The last two decades have provided analysts with more sensitive technology, enabling scientists from all analytical fields to see what they were not able to see just a few years ago. This increased sensitivity has allowed drug detection at very low concentrations and testing in unconventional samples (e.g., hair, oral fluid and sweat), where despite having low analyte concentrations has also led to a reduction in sample size. Along with this reduction, and as a result of the use of excessive amounts of potentially toxic organic solvents (with the subsequent environmental pollution and costs associated with their proper disposal), there has been a growing tendency to use miniaturized sampling techniques. Those sampling procedures allow reducing organic solvent consumption to a minimum and at the same time provide a rapid, simple and cost-effective approach. In addition, it is possible to get at least some degree of automation when using these techniques, which will enhance sample throughput. Those miniaturized sample preparation techniques may be roughly categorized in solid-phase and liquid-phase microextraction, depending on the nature of the analyte. This paper reviews recently published literature on the use of microextraction sampling procedures, with a special focus on the field of forensic toxicology.

Undesirable sulphur and carbonyl flavor compounds in UHT milk: a review

Ultra High Temperature (UHT) processing leads to the formation of "cooked" and "flat" flavors in milk. These undesirable notes occur due to the volatile formation of a variety of sulphur containing compounds, methyl ketones and aliphatic aldehydes, derived from the constituents of the milk's matrix during thermal processing and storage. The "cooked" flavor of UHT milk is associated with the presence of a variety of sulphur containing compounds while the "stale" flavor is characterized by the dissipation of these sulphur volatiles and an increase of the formation and presence of both methyl ketones and aliphatic aldehydes over time. The extent to which the individual volatiles contribute to the overall flavor of UHT milk is not clear. The proposed formation of these volatiles, that is, the methods to control the intensity of "cooked" and "stale" flavors associated with UHT milk and extraction techniques for the isolation of these volatiles from milk, have been reviewed.

Determination of different recreational drugs in hair by HS-SPME and GC/MS

A simple procedure combining headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS) to detect and quantify amphetamines, ketamine, methadone, cocaine, cocaethylene and Delta(9)-tetrahydrocannabinol (THC) in hair is described. This procedure allows, in a single sample, even scant, analysis of drugs requiring different analytical conditions. A hair sample (10 mg) is washed and subjected to acidic hydrolysis. Then the HS-SPME is carried out (10 min at 90 degrees C) for amphetamines, ketamine, methadone, cocaine and cocaethylene. For derivatization of analytes, the fibre is introduced into the headspace of another closed vial containing acetic anhydride. After a chromatographic run, an alkaline hydrolysis for THC analysis is carried out in the same vial containing the hair sample previously used. For adsorption, the solid-phase microextraction needle is inserted into the headspace of the vial and the fibre is exposed for 30 min at 150 degrees C. For derivatization of analytes, the fibre is introduced into the headspace of another closed vial containing N-methyl-N-(trimethylsilyl)trifluoroacetamide. The GC/MS parameters were the same for both chromatographic runs. The linearity was proved to be between 0.01 and 10.00 ng/mg. The repeatability (intra- and interday precision) was below 10% as the coefficient of variation for all compounds. The accuracy, as the relative recovery, was 96.2-103.5% (spiked samples) and 88.6-101.7% (quality control sample). The limit of detection ranged from 0.01 to 0.12 ng/mg, and the limit of quantification ranged from 0.02 to 0.37 ng/mg. Application of the procedure to real hair samples is described. To the best of our knowledge, the proposed procedure combining HS-SPME and GC/MS is the first one be to successfully applied to the simultaneous determination of most of the common recreational drugs, including THC, in a single hair sample.

Fundamentals and applications of needle trap devices: a critical review

The needle trap device (NTD) is an extraction trap that contains a sorbent inside a small needle, through which fluid can be actively drawn into and out of by a gas-tight syringe or pump, or analytes can be introduced passively to the trap by diffusion. The needle trap (NT) is a potentially solventless sampling technique/sample preparation and introduction device. Both fluid-borne analytes and particles can be trapped inside the needle and then adsorbed analytes are desorbed in an inlet of analytical instrument and introduced for identification and quantification. The fluid may be either gaseous or liquid. The objectives of this critical review are to summarize the theory of the sampling process for both active and passive time-average extraction modes in addition to outlining the evolution of the technology and main applications.