Conductive vial electromembrane extraction of opioids from oral fluid

New robust and efficient liquid membranes for conductive vial electromembrane extraction of acids with low to moderate hydrophilicity in human plasma

The current paper reports two new, robust, and efficient conditions for electromembrane extraction of acidic substances from human plasma. Two systems were developed based on eutectic solvents: A1 ("A" for acid) comprised dodecyl methyl sulfoxide and thymol in 1:2 ratio (w/w) as liquid membrane, while A2 used [6-methylcoumarin:thymol (1:2)]:2-nitrophenyl octyl ether in 2:1 ratio (w/w). The performance of A1 and A2 was characterized by extraction of 31 acidic model analytes (pharmaceutical drugs and nutrients) spiked into 100 µL human plasma diluted 1:1 (v/v) with phosphate buffer pH 7.4. The acceptor solution was 50 mM NH4HCO3 buffer pH 10.0, and extraction was performed at an agitation rate of 750 RPM. Voltage and extraction time were 30 V for 30 min and 10 V for 20 min for A1 and A2, respectively. Under optimal conditions, A1 extracted analytes with 1.8 ≤ log P ≤ 6.0 with an average recovery (R) of 85.1%, while A2 extracted in a range of 0.5 ≤ log P ≤ 6.0 with an average recovery of 79.9%. Meanwhile, extraction current was low at 9 and 26 µA, respectively, which is indicative of good system robustness. Using UHPLC-MS/MS analysis of the acceptor solution, repeatability of the A1 and A2 methods was determined to be 2.8-7.7% and 3.3-9.4% for R > 40%, matrix effects were 82-117% and 84-112%, respectively, and linear calibration curves were obtained. The performance and compatibility with human plasma represent a major improvement over previous state-of-the-art liquid membranes for acidic analytes, namely 1-octanol.

Drug detection in oral fluid and urine after single therapeutic doses of dexamphetamine, lisdexamphetamine, and methylphenidate in healthy volunteers

Dexamphetamine, lisdexamphetamine, and methylphenidate are central stimulant drugs widely used to treat attention-deficit/hyperactivity disorder (ADHD), but poor adherence may lead to treatment failure, and the drugs are also subject to misuse and diversion. Drug analysis in oral fluid may thus be useful for monitoring adherence and misuse. We measured drug concentrations in oral fluid and urine after controlled dosing to investigate detection windows and evaluate the chosen cutoffs. Healthy volunteers ingested single oral doses of 10 mg dexamphetamine (n = 11), 30 mg lisdexamphetamine (n = 11), or 20 mg methylphenidate (n = 10), after which they collected parallel oral fluid and urine samples every 8 h for 4-6 days. Amphetamine (analytical cutoff, oral fluid: 1.5 ng/mL; urine: 50 ng/mL), methylphenidate (oral fluid: 0.06 ng/mL), and ritalinic acid (urine: 500 ng/mL) were analyzed using fully validated chromatographic methods. The median time from ingestion to the last detection in oral fluid was 67 ± 4.9 h (lisdexamphetamine) and 69 ± 8.8 h (dexamphetamine) for amphetamine and 36 ± 2.5 h for methylphenidate. This was comparable to urine (77 ± 5.1 h for lisdexamphetamine, 78 ± 4.5 h for dexamphetamine, and 41 ± 2.4 h for ritalinic acid). The interindividual variability in detection times was large, probably in part due to pH-dependent disposition. Using a logistic regression approach, we found similar detection rates as a function of time since intake in urine and oral fluid with the chosen cutoffs, with a high degree of probability for detection at least 24 h after intake of a low therapeutic dose. This demonstrates the usefulness of oral fluid as a test matrix to assess adherence to ADHD medications, provided that the analytical method is sensitive, requiring a cutoff as low as 0.1 ng/mL for methylphenidate. Detection windows similar to those in urine may be achieved for amphetamine and methylphenidate in oral fluid.

Metal-organic framework-801@MXene nanocomposites as a coating for headspace solid-phase microextraction of methadone and tramadol from biological samples via gas chromatography-mass spectrometry

MOF-801@MXene nanocomposites are introduced as a new solid-phase microextraction coating. This structure was easily prepared by one-pot solvothermal route. The MOF-801@MXene, MOF-801, and MXene were characterized by various analysis techniques such as field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray powder diffraction, and Brunauer-Emmett-Teller. The coating was used in the headspace solid-phase microextraction of methadone and tramadol in biological samples. The separation and determination of the analytes were performed by gas chromatography-mass spectrometry. The effective parameters on the extraction efficiency of the analytes, such as extraction time and temperature, desorption time and temperature, salt concentration, and NaOH concentration, were optimized by experimental design method. Under optimal conditions, low limits of detection in the range 0.03-0.15 µg L-1, wide linearity in the range 0.10-250.00 µg L-1, and good reproducibility (RSD = 5.3 to 7.4% for n = 3) were achieved. Under optimal conditions, microextraction of methadone and tramadol was performed in real hair, urine, and plasma samples, and satisfactory results were obtained.

Electromembrane extraction of drugs of abuse and prescription drugs from micropulverized hair

Hair analysis can provide chronological insights into past drug use for months to years after drug administration. In comparison to analyses from other biological matrices, such as blood and urine, sample pretreatment is often tedious and not environmental friendly. In this study, we present a more environmental friendly approach to hair analysis using micropulverized hair and electromembrane extraction for the efficient extraction of 15 drugs of abuse, prescription drugs, and metabolites from hair. The optimized extraction method, involving micropulverization, demonstrated comparable yields to the standard approach of cutting and overnight incubation. A 15-min extraction method using a commercial electromembrane extraction prototype was developed and validated according to forensic guidelines, using only 10 µL of organic solvent per sample. The final method, employing HPLC-MS-MS with a biphenyl column, exhibited good linearity, precision, and sensitivity. An AgreePrep assessment comparing the environmental impact of our method with the standard routine method, involving overnight incubation and conventional liquid-liquid extraction, was conducted. This is the first time micropulverized hair has been subjected to electromembrane extraction.

Bioinspired composite packed in blunt needles, integrated microextraction and determination of oxycodone and naloxone in saliva by substrate spray mass spectrometry

BACKGROUND

Opioids are effective painkillers used for medical purposes. Their prolonged ingestion can provoke some side effects (including overdose or constipation) that are minimized by using opioid antagonists (e.g., naloxone). The rapid determination of opioids and their antagonists in biosamples is essential for an effective medical treatment. The direct combination of sample preparation and mass spectrometry (MS) fits well in this scenario. It can speed up the analysis achieving a good selectivity, which relies on the sample preparation and MS, and sensitivity levels.

RESULTS

This article presents a novel substrate-spray mass spectrometry interface based on a polydopamine-cotton (PDA-Cel) composite hosted inside the inner diameter of a 14-gauge blunt needle to determine oxycodone and naloxone in saliva samples. The needle is used as a microextraction device and a substrate for mass spectrometric analysis. The lack of sharpness of the 14-gauge (14G) blunt needles challenges the formation of the electrospray (ESI), and a commercial 10 μL pipette tip is proposed as a simple solution to this shortcoming. Under the optimum parameters, the proposed method was validated, obtaining limits of detection lower than 0.6 μg L-1, linear range up to 200 μg L-1, and linearity better than 0.9915. Relative standard deviation (RSD) and relative recoveries (RR) were studied at three different concentration levels (2, 40, and 200 μg L-1). RSD values were better than 20.7 %, and RR ranged from 90 to 114 %. Finally, a positive sample from a patient under medical treatment was analyzed.

SIGNIFICANCE AND NOVELTY

14G blunt needles have been demonstrated as effective extraction devices due to their low price (<0.15 € per extraction unit), their better safety (avoiding finger pricking), and their higher hosting capacity (up to 8 mg of sorbent). The conductivity of stainless steel permits their use as electrospray emitters, making their direct combination to MS easier. The large variety of fibrous sorbents makes this approach versatile enough to be adapted to other analytical problems.

Extraction performance of electromembrane extraction and liquid-phase microextraction in prototype equipment

In this comparative study, the performance of liquid-phase microextraction and electromembrane extraction in prototype equipment was evaluated for extraction of ninety basic substances from plasma. Using a commercial EME device based on conductive vials enabled a standardized and comprehensive comparison between the two methods. Extractions were performed from a pH-adjusted donor solution, across an organic liquid membrane immobilized in a porous polypropylene membrane, and into an acidic acceptor solution. In LPME, dodecyl acetate was used as the extraction solvent, while 2-nitrophenyl octyl ether was used for EME with an electric field applied across the system. To assess the extraction performance, extraction recovery plots and extraction time curves were constructed and analyzed. These plots provided insights into the efficiency and effectiveness of LPME and EME, allowing users to make better decisions about the most suitable method for a specific bioanalytical application. Both LPME and EME were effective for substances with 2.0 < log P < 4.0, with EME showing faster extraction kinetics. Small (200 µL) and large vials (600 µL) were compared, showing that smaller vials improved kinetics markedly in both techniques. Carrier-mediated extraction showed improved performance for analytes with log P < 2 in EME, however, with some limitations due to system instability. This is, to our knowledge, the first time LPME was performed in the commercial vial-based equipment. An evaluation of vial-based LPME investigating linearity, precision, accuracy, and matrix effects showed promising results. These findings contribute to a general understanding of the performance differences in vial-based LPME and EME.