Polyoxometalate-Based Frameworks as Adsorbents for Drug of Abuse Extraction from Hair Samples.

The linkage of molecular components into functional heterogeneous framework materials has revolutionized modern materials chemistry. Here, we use this principle to design polyoxometalate-based frameworks as high affinity adsorbents for drugs of abuse, leading to their application in solid-phase extraction analysis. The frameworks are assembled by the reaction of a Keggin-type polyanion, [SiW12O40]4-, with lanthanoids Dy(III), La(III), Nd(III), and Sm(III) and the multidentate linking ligand 1,10-phenanthroline-2,9-dicarboxylic acid (H2PDA). Their reaction leads to the formation of crystalline 1D coordination polymers. Because of the charge mismatch between the lanthanoids (+3) and the dodecasilicotungstate (-4), we observe incorporation of the PDA2- ligands into crystalline materials, leading to four polyoxometalate-based frameworks where Keggin-type heteropolyanions are linked by cationic {Lnn(PDA)n} groups (Ln = Dy (1), La (2), Nd (3), and Sm (4)). Structural analysis of the polyoxometalate-based frameworks suggested that they might be suitable for surface binding of common drugs of abuse via supramolecular interactions. To this end, they were used for the extraction and quantitative determination of four model drugs of abuse (amphetamine, methamphetamine, codeine, and morphine) by using micro-solid-phase extraction (D-µSPE) and high-performance liquid chromatography (HPLC). The method showed wide linear ranges, low limits of detection (0.1-0.3 ng mL-1), high precision, and satisfactory spiked recoveries. Our results demonstrate that polyoxometalate-based frameworks are suitable sorbents in D-µSPE for molecules containing amine functionalities. The modular design of these networks could in the future be used to expand and tune their substrate binding behavior.

Epoxide-derived mixed-mode chromatographic stationary phases for separation of active substances in fixed-dose combination drugs.

A method for the preparation of novel mixed-mode reversed-phase/strong cation exchange stationary phase for the separation of fixed-dose combination drugs has been developed. An epoxysilane bonded silica prepared by vapor phase deposition was used as a starting material to produce diol, octadecyl, sulfonate, and mixed octadecyl/sulfonate groups bonded silica phases. The chemical structure and surface coverage of the functional groups on these synthesized phases were confirmed by fourier-transform infrared and solid-state 13 C NMR spectroscopy and elemental analysis. Alkylbenzene homologs, basic drugs, nucleobases and alkylaniline homologs were used as probes to demonstrate the reversed-phase, ion exchange, hydrophilic interaction and mixed-mode retention behaviors of these stationary phases. The octadecyl/sulfonate bonded silica exhibits pronounced mixed-mode retention behavior and superior retentivity and selectivity for alkylaniline homologs. The mixed-mode retention is affected by either ionic or solvent strength in the mobile phase, permiting optimization of a separation by fine tuning these parameters. The mixed-mode stationary phase was applied to separate two fixed-dose combination drugs: compound reserpine tablets and compound methoxyphenamine capsules. The results show that simultaneous separation of multiple substances in the compound dosage can be achieved on the mixed-mode phase, which makes multi-cycles of analysis for multiple components obsolete.

Hybrid Solid-Phase Extraction for Selective Determination of Methamphetamine and Amphetamine in Dyed Hair by Using Gas Chromatography-Mass Spectrometry.

Sample preparation is an important step in the isolation of target compounds from complex matrices to perform their reliable and accurate analysis. Hair samples are commonly pulverized or processed as fine cut, depending on preference, before extraction by techniques such as solid-phase extraction (SPE), liquid-liquid extraction, and other methods. In this study, a method based on hybrid solid-phase extraction (hybridSPE) and gas chromatography-mass spectrometry (GC-MS) was developed and validated for the determination of methamphetamine (MA) and amphetamine (AP) in hair. The hair samples were mechanically pulverized after washing with de-ionized water and acetone. The samples were then sonicated in methanol at 50 °C for 1 h and centrifuged at 50,000× g for 3 min. The supernatants were transferred onto the hybridSPE cartridge and extracted using 1 mL of 0.05 M methanolic hydrogen chloride. The combined solutions were evaporated to dryness, derivatized using pentafluoropropionic anhydride, and analyzed by GC-MS. Excellent linearity (R2 > 0.9998) was achieved in the ranges of 0.05-5.0 ng/mg for AP and 0.1-10.0 ng/mg for MA. The recovery was 83.4-96.8%. The intra- and inter-day accuracies were -9.4% to 5.5% and -5.1% to 3.1%, while the intra- and inter-day precisions were within 8.3% and 6.7%, respectively. The limits of detections were 0.016 ng/mg for AP and 0.031 ng/mg for MA. The validated hybridSPE method was applied to dyed hair for MA and AP extraction and compared to a methanol extraction method currently being used in our laboratory. The results showed that an additional hybridSPE step improved the recovery by 5.7% for low-concentration quality control (QC) samples and by 24.1% for high-concentration QC samples. Additionally, the hybridSPE method was compared to polymeric reversed-phase SPE methods, and the absolute recoveries for hybridSPE were 50% and 20% greater for AP (1.5 ng/mg) and MA (3.0 ng/mg), respectively. In short, the hybridSPE technique was shown to minimize the matrix effects, improving GC-MS analysis of hair. Based on the results, the proposed method proved to be effective for the selective determination of MA and AP in hair samples.

Simultaneous enantioseparation of methcathinone and two isomeric methylmethcathinones using capillary electrophoresis assisted by 2-hydroxyethyl-ß-cyclodextrin.

Methcathinone (ephedrone), 4-methylmethcathinone (mephedrone), and 3-methylmethcathinone (metaphedrone) are toxicologically-important cathinone derivatives used commonly as designer drugs. In this work we show the first method allowing to separate simultaneously all these molecules in a chiral medium, ensuring good resolution between all enantiomers. Eight cyclodextrins have been tested as potential chiral selectors, the best results were obtained with 2-hydroxyethyl-ß-cyclodextrin, unreported so far for efficient separation of cathinones. After optimization, the method was calibrated and validated with and without the use of internal standard. The addition of standard improved an overall repeatability and precision, the use of electrophoretic mobility ratio was especially favorable (RSD < 1%). It was demonstrated that the method may be easily extended by introducing the additional cathinone-related drugs to the sample, maintaining satisfactory separation efficiency.

Resolution of methoxyphenamine and its analogues on a chiral stationary phase based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid.

A liquid chromatographic chiral stationary phase, which contains two N-CH3 amide connecting groups, based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid was first applied to the resolution of methoxyphenamine (2-methoxy-N-methylamphetamine, a ß-adrenergic receptor agonist used as a bronchodilator). The resolution of methoxyphenamine on the chiral stationary phase containing two N-CH3 amide connecting groups was quite successful with the separation factor (α) of 1.42 and resolution (RS ) of 4.22 compared with those (α of 1.09 and RS of 1.55) on the chiral stationary phase containing two N-H amide connecting groups. In addition, the chiral stationary phase containing two N-CH3 amide connecting groups was applied to the resolution of methoxyphenamine analogues. From the comparison of the resolution results of methoxyphenamine with those of methoxyphenamine analogues on the chiral stationary phase containing two N-CH3 amide connecting groups, the N-methyl group and the 2-methoxyphenyl group of methoxyphenamine were elucidated to be the structurally essential parts for the resolution on the chiral stationary phase.

Peptide Metal-Organic Frameworks for Enantioselective Separation of Chiral Drugs.

We report the use of a chiral Cu(II) 3D metal-organic framework (MOF) based on the tripeptide Gly-l-His-Gly (GHG) for the enantioselective separation of metamphetamine and ephedrine. Monte Carlo simulations suggest that chiral recognition is linked to preferential binding of one of the enantiomers as a result of either stronger or additional H-bonds with the framework that lead to energetically more stable diastereomeric adducts. Solid-phase extraction of a racemic mixture by using Cu(GHG) as the extractive phase permits isolating >50% of the (+)-ephedrine enantiomer as target compound in only 4 min. To our knowledge, this represents the first example of a MOF capable of separating chiral polar drugs.

Hematocrit-Independent Quantitation of Stimulants in Dried Blood Spots: Pipet versus Microfluidic-Based Volumetric Sampling Coupled with Automated Flow-Through Desorption and Online Solid Phase Extraction-LC-MS/MS Bioanalysis.

A workflow overcoming microsample collection issues and hematocrit (HCT)-related bias would facilitate more widespread use of dried blood spots (DBS). This report describes comparative results between the use of a pipet and a microfluidic-based sampling device for the creation of volumetric DBS. Both approaches were successfully coupled to HCT-independent, fully automated sample preparation and online liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis allowing detection of five stimulants in finger prick blood. Reproducible, selective, accurate, and precise responses meeting generally accepted regulated bioanalysis guidelines were observed over the range of 5-1000 ng/mL whole blood. The applied heated flow-through solvent desorption of the entire spot and online solid phase extraction (SPE) procedure were unaffected by the blood's HCT value within the tested range of 28.0-61.5% HCT. Enhanced stability for mephedrone on DBS compared to liquid whole blood was observed. Finger prick blood samples were collected using both volumetric sampling approaches over a time course of 25 h after intake of a single oral dose of phentermine. A pharmacokinetic curve for the incurred phentermine was successfully produced using the described validated method. These results suggest that either volumetric sample collection method may be amenable to field-use followed by fully automated, HCT-independent DBS-SPE-LC-MS/MS bioanalysis for the quantitation of these representative controlled substances. Analytical data from DBS prepared with a pipet and microfluidic-based sampling devices were comparable, but the latter is easier to operate, making this approach more suitable for sample collection by unskilled persons.

Analysis of amphetamine and methamphetamine in municipal wastewater influent and effluent using weak cation-exchange SPE and LC-MS/MS.

Amphetamine and methamphetamine are emerging contaminants-those for which no regulations currently require monitoring or public reporting of their presence in our water supply. In this research, a protocol for weak cation-exchange (WCX) SPE coupled with LC-MS/MS was developed for determination of emerging contaminants amphetamine and methamphetamine in a complex wastewater matrix. Gradient LC parameters were adjusted to yield baseline separation of methamphetamine from other contaminants. Methamphetamine-D5 was used as the internal standard (IS) to compensate for sample loss during SPE and for signal loss during MS (matrix effects). Recoveries were 102.1 ± 7.9% and 99.4 ± 4.0% for amphetamine and methamphetamine, respectively, using WCX sorbent. Notably, methamphetamine was determined to be present in wastewater influent at each sampling date tested. Amphetamine was present in wastewater influent on two of four sampling dates. Amphetamine concentrations ranged from undetectable to 86.4 ng/L in influent, but it was undetectable in wastewater effluent. Methamphetamine was detected in influent at concentrations ranging from 27.0-60.3 ng/L. Methamphetamine concentration was reduced but incompletely removed at this facility. Although absent in one post-UV effluent sample, concentrations of methamphetamine ranged from 10.8-14.8 ng/L.

Forensic electrochemistry applied to the sensing of new psychoactive substances: electroanalytical sensing of synthetic cathinones and analytical validation in the quantification of seized street samples.

The electrochemical sensing of new psychoactive substance(s) (NPSs), synthetic cathinone derivatives also termed "legal highs", are explored with the use of metallic modified screen-printed electrochemical sensors (SPES). It is found that no significant electrochemical enhancement is evident with the use of either in situ bismuth or mercury film modified SPES compared to the bare underlying electrode substrate. In fact, the direct electrochemical reduction of the cathinone derivatives mephedrone (4-methylmethcathinone; 4-MMC) and 4'-methyl-N-ethylcathinone (4-methylethcathinone; 4-MEC) is found to be possible for the first time, without heavy metal catalysis, giving rise to useful voltammetric electroanalytical signatures in model aqueous buffer solutions. This novel electroanalytical methodology is validated toward the determination of cathinone derivatives (4-MMC and 4-MEC) in three seized street samples that are independently analyzed with high-performance liquid chromatography (HPLC) wherein excellent agreement between the two analytical protocols is found. Such an approach provides a validated laboratory tool for the quantification of synthetic cathinone derivatives and holds potential for the basis of a portable analytical sensor for the determination of synthetic cathinone derivatives in seized street samples.

Methamphetamine detection using portable capillary electrophoresis coupled with a swab-based extraction device.

Methamphetamine (MA) is one of the most virulent illicit drugs that can be synthesized from household materials leading to its prevalent trafficking and local manufacturing in clandestine drug laboratories (clan labs). The significant problems of tracing MA in clan labs and monitoring drug abusers lie in the lag time between sample collection and analysis and the number of tests done. Capillary electrophoresis (CE) is a rapid separation technique amenable to miniaturization and field testing. Herein, we developed a simple transient isotachophoretic (tITP)-CE method to detect MA and its precursor pseudoephedrine (PSE) in clan labs and non-invasive biological fluids. The method was implemented on the ETD-100, a commercial fully automated portable CE instrument with an integrated swab-based extraction system. Within 2 min of insertion of the swab, MA and PSE were automatically extracted with a leading electrolyte (LE) and then separated on covalently modified capillaries. The ETD-100 showed a limit of detection (LOD) and quantification (LOQ) of MA 0.02 and 0.05 µg/swab and 0.02 and 0.06 µg/swab of PSE, with an enhancement factor of 118 and 328, respectively, when compared to a normal non-tITP injection. The intra and inter-day relative standard deviation in terms of migration time were in the range of 0.75-1.93 % for both MA and PSE and were 2.0-2.4 % for both MA and PSE peak height. The method was demonstrated with the detection of spiked MA and PSE on different household materials as well as in non-invasive biological fluids with a recovery above 60 %.

Separation of isotopologues of amphetamine with various degree of deuteration on achiral and polysaccharide-based chiral columns in high-performance liquid chromatography.

Hydrogen/deuterium (H/D) isotope effects are not unusual in chromatography and such phenomena have been observed in both gas- and liquid-phase separations. Despite the numerous reports on this topic, the understanding of mechanisms and the underlying noncovalent interactions at play remains rather challenging. In our recent study, we reported baseline separation of isotopologoues of some amphetamine (AMP) derivatives on achiral and polysaccharide-based chiral columns, as well as some correlations between the degree of separation of enantiomers and isotopologues on (the same) polysaccharide-based chiral column(s). Following our previous findings on isotope effects in high-performance liquid chromatography, we report herein a comparative study on the isotope effects observed with AMP and methamphetamine (MET). The impact of some pivotal factors such as the number of deuterium atoms part of AMP isotopologues, the structure of its isotopomers, the chemical structure of the achiral and chiral stationary phases used in this study, and the use of methanol- vs acetonitrile-containing mobile phases on the isotope effects was examined and discussed. Quantitative correlations between the observed isotope effects and the enantioselectivity of the chiral columns used are also shortly discussed. Furthermore, considering the chromatographic results as benchmark experimental data, we attempted to elucidate the molecular bases of the observed phenomena using quantum mechanics calculations.

A comprehensive chromatographic comparison of amphetamine and methylamphetamine extracted from river water using molecular imprinted polymers and without the need for sample derivatization.

This work explores the differences between two GCMS instruments for the determination of amphetamine and methylamphetamine extracted from water samples (ultra pure water and river water) without the necessity for derivatization. The instruments contained different generations of gas chromatograph and mass selective detector components and revealed significantly different results when presented with the same samples. The extraction methodology also compared two SPE systems. The extraction efficiency of commercially available molecular imprinted polymers as a sorbent in SPE was compared with commonly used hydrophilic balance sorbent. Molecular imprinted polymers provided excellent recoveries (81 ± 2% and 108 ± 3% at 30 µg L(-1), and 94 ± 2% and 94 ± 2% at 200 µg L(-1) for amphetamine and methylamphetamine, respectively). The best LOD obtained was sufficient for the determination of both drugs extracted from river water (0.029 ± 0.003 and 0.015 ± 0.004 µg L(-1) for amphetamine and methylamphetamine, respectively). These were comparable to literature values obtained through conventional extraction and analysis using LC-MS/MS but had the advantage of being achieved using an underivatized GCMS method.

Chiral gas chromatography as a tool for investigations into illicitly manufactured methylamphetamine.

The aim of this study was to develop a chiral gas chromatographic method for the separation of compounds likely to be found in the EMDE synthesis of methylamphetamine, a heavily abused stimulant drug. Here we describe the separation of the enantiomers of ephedrine, pseudoephedrine, chlorinated intermediates and methylamphetamine using fluorinated acid anhydrides as chemical derivatization reagents prior to gas chromatographic analysis on a 2,3-di-O-methyl-6-t-butyl silyl-ß-cyclodextrin stationary phase (CHIRALDEX™ B-DM). Separation of the enantiomers of pseudoephedrine, methylamphetamine and chloro-intermediates was achieved using PFPA derivatization, and enantiomers of ephedrine using TFAA derivatization, in run times of less than 40 minutes. The use of HFBA as a derivatization reagent for this set of analytes is also discussed.

[NMR Study of the Discrimination of Enantiomers of Methamphetamine and Its Raw Materials Using Chiral Solvating Agents].

Some controlled substances, such as stimulants and narcotics, have asymmetric carbons in their molecules. Because the enantiomers do not always show the same pharmacological effects, and there are substances with different controls due to differences in their stereochemistry, a simple and unambiguous method for assessment of the composition of enantiomers is necessary. In this study, to develop a simple and rapid stereoscopic identification method for methamphetamine and its raw materials (ephedrine and pseudoephedrine), the 1H-NMR method was studied using three commercially available chiral solvating agents (CSAs); 1,1'-bi(2-naphthol)(BINOL), 2,2,2-trifluoro-1-(9-anthryl)ethanol (TFAE) and α-methoxy-α-(trifluoromethyl)phenylacetic acid (MTPA). In addition, the accuracy of the optical purity, which was measured using samples mixed with enantiomers in various ratios, was investigated. The NMR peaks of the enantiomers were separated by adding (R)- or (S)-form of BINOL, TFAE or MTPA to the chloroform-d solution of methamphetamine, ephedrine or pseudoephedrine. A sufficient discrimination of enantiomers was obtained by adding about 10 equal amounts of each CSA to the solutions. With regard to the optical purity, it was possible to determine accurately the mixing of small amounts of enantiomers of about 5% even if the NMR peaks did not reach the baseline separation, when impurity peaks do not overlap. This method will be one of the useful techniques for the rapid and simple discrimination of enantiomers of illegal methamphetamine and its raw materials.

Development of a Pencil Drawn Paper-based Analytical Device to Detect Lysergic Acid Diethylamide (LSD)*, †.

The need for agile and proper identification of drugs of abuse has encouraged the scientific community to improve and to develop new methodologies. The drug lysergic acid diethylamide (LSD) is still widely used due to its hallucinogenic effects. The use of voltammetric methods to analyze narcotics has increased in recent years, and the possibility of miniaturizing the electrochemical equipment allows these methods to be applied outside the laboratory; for example, in crime scenes. In addition to portability, the search for affordable and sustainable materials for use in electroanalytical research has grown in recent decades. In this context, employing paper substrate, graphite pencil, and silver paint to construct paper-based electrodes is a great alternative. Here, a paper-based device comprising three electrodes was drawn on 300 g/m2 watercolor paper with 8B pencils, and its efficiency was compared to the efficiency of a commercially available screen-printed carbon electrode. Square wave voltammetry was used for LSD analysis in aqueous medium containing 0.05 mol/L LiClO4 . The limits of detection and quantification were 0.38 and 1.27 µmol/L, respectively. Both electrodes exhibited a similar voltammetric response, which was also confirmed during analysis of a seized LSD sample, with recovery of less than 10%. The seized samples were previously analyzed by GCMS technique, employing the full scan spectra against the software spectral library. The electrode selectivity was also tested against 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine. It was possible to differentiate these compounds from LSD, indicating that the developed paper-based device has potential application in forensic chemistry analyses.

Addressing the instability issue of dopamine during microdialysis: the determination of dopamine, serotonin, methamphetamine and its metabolites in rat brain.

Dopamine is a catecholamine neurotransmitter that degrades rapidly in aqueous solutions; hence, its analysis following brain microdialysis is challenging. The aim of the current study was to develop and validate a new microdialysis coupled LC-MS/MS system with improved accuracy, precision, simplicity and turnaround time for dopamine, serotonin, methamphetamine, amphetamine, 4-hydroxymethamphetamine and 4-hydroxyamphetamine analysis in the brain. Dopamine degradation was studied with different stabilizing agents under different storage conditions. The modified microdialysis system was tested in vitro, and was optimized for best probe recovery, assessed by %gain. LC-MS/MS assay was developed and validated for the targeted compounds. Stabilizing agents (ascorbic acid, EDTA and acetic acid) as well as internal and cold standards were added on-line to the dialysate flow. Assay linearity range was 0.01-100 ng/mL, precision and accuracy passed criteria, and LOQ and LLOQ were 0.2 and 1.0 pg, respectively. The new microdialysis coupled LC-MS/MS system was used in Wistar rats striatum after 4 mg/kg subcutaneous methamphetamine. Methamphetamine rapidly distributed to rat striatum reaching an average ~200 ng/mL maximum, ~82.5 min post-dose. Amphetamine, followed by 4-hydroxymethamphetamine, was the most abundant metabolite. Dopamine was released following methamphetamine injection, while serotonin was not altered. In conclusion, we proposed and tested an innovative and simplified solution to improve stability, accuracy and turnover time to monitor unstable molecules, such as dopamine, by microdialysis.

Metal organic framework based carbon porous as an efficient dispersive solid phase extraction adsorbent for analysis of methamphetamine from urine matrix.

Carboxylated carbon porous adsorbent was derived from zeolite imidazole framework (ZIF-8) via carbonization of ZIF-8 under a nitrogen atmosphere. The synthesized carboxylated adsorbent was fully characterized by various techniques including Fourier transform spectroscopy (FTIR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and zeta potential analysis. The carboxylated adsorbent was applied as dispersive solid phase extraction (DSPE) adsorbent for efficient extraction of methamphetamine (MET) from biological urine samples. Several extraction parameters influencing the extraction efficiency were investigated and the calibration curve was plotted under optimized conditions in urine media. The method showed a good linearity in the range of 50-2500 ng/mL. The limit of detection (LOD) and limit of quantification (LOQ) was 10 and 35.80 ng/mL, respectively. A satisfactory analysis of the positive real samples with the recovery of 99.83% confirms the applicability of the proposed method in different clinical and forensic laboratories.

Postmortem analysis of famprofazone and its metabolites, methamphetamine and amphetamine, in porcine bone marrow.

Forensic toxicologists typically work with body fluids, such as blood and urine, or visceral tissues. The analysis of alternative samples, such as bone marrow, can be requested when the commonly used samples are unavailable due to an extended time lapse between the time of death and collection of the material to be analysed. In this study, a method for the analysis of the lipophilic drug famprofazone (FA) and its metabolites, methamphetamine (MA) and amphetamine (AM), in bone marrow was developed, validated and applied to bone marrow from pigs given controlled doses of famprofazone. This method involves enzymatic bone-cleaning, fragmentation of the bones with the assistance of a micro electric motor, optimization of clean-up and LLE (liquid/liquid extraction) conditions and determination by GC/MS. After evaluation through statistical tests, such as Shapiro Wilk for normality and Cochran for homoscedasticity, a linear model was applied in the range of 100 (LOQ) - 2000 ng g-1. Inter-day precision and bias was always < 4.6%. In real sample analysis, bone marrow FA and MA concentrations ranged from 103 to 232 and from 174 to 267 ng g-1, respectively; AM was not detected. The obtained results are useful for application in forensic toxicological protocols (human autopsy cases) and as a starting point for the development of further analytical tools.

Developed nano carbon-based coating for simultaneous extraction of potent central nervous system stimulants from urine media by stir bar sorptive extraction method coupled to high performance liquid chromatography.

A nano graphene oxide sol-gel composite (NGO/sol-gel) applied as a coating of a capillary glass tube stir bar to develop a novel stir bar sorptive extraction (SBSE) method for simultaneous extraction of amphetamine (AMP) and methamphetamine (MET) from biological urine sample. Lab-synthesized NGO was applied with methyltrimethoxysilane (MTMOS) and Tetraethoxysilane (TEOS) as sol-gel precursor. NGO/sol-gel was deposited on the surface of a capillary glass tube to prepare stir bar sorptive extraction adsorbent by a simple and fast method. The scanning electron micrograph images showed a three dimensional structure of lab-made device suitable for SBSE method for simultaneous extraction of AMP and MET. Effective extraction parameters were investigated. Through studied suitable extraction conditions, satisfactory linearity was achieved in the concentration range of 50-2000 ngmL-1 for AMP and 40-2500 ngmL-1 for MET. The relative recovery of the analytes were 99.5 and 99.7% for AMP and MET, respectively for positive urine samples were studied by novel introduced method. The results cleared that NGO/sol-gel composite could be used as practical method in laboratories as an efficient SBSE adsorbent for drugs determination in urine matrix.

A systematic investigation of forensic hair decontamination procedures and their limitations.

The effectiveness of decontamination procedures used for the removal of external drug contamination in forensic hair analysis is an ongoing debate. This investigation evaluated wash methods complying with Society of Hair Testing (SoHT) guidelines and their capacity to remove cocaine (COC) and methamphetamine (MA) from artificially contaminated hair. The most effective decontamination method was determined using a systematic approach, involving (1) an initial washing solvent screen, (2) optimization of wash duration, (3) comparison of sequential wash methods, and (4) reanalysis of clinical hair samples. For analysis, hair was subjected to micro-pulverized methanolic extraction prior to quantitation by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Methanol (MeOH) and 0.1 M phosphate buffer (pH 6) were the most effective organic and aqueous solvents, respectively, removing 28%-38% of COC and 16%-31% of MA. Wash durations longer than 30-60 minutes did not remove additional amounts, and a more efficient sequential wash method was subsequently developed. Despite this, the interpretation of reportable results relative to the SoHT cut-off levels was unchanged for most clinical hair samples reanalyzed after washing by agitation for 30 minutes with MeOH. These findings highlight the inability of decontamination solvents to completely remove external COC and MA contamination from hair, including wash methods adhering to SoHT guidelines.