Two-side slug-flow microextraction coupled with ion mobility spectrometry for fast quantification of amphetamine and methamphetamine in human urine

Rapid and accurate quantification of amphetamine and methamphetamine in human urine by antibody decorated magnetite nanoparticles coupled with matrix-assisted laser desorption ionization time-of-flight mass spectrometer analysis

Solvent-bar microextraction—Using a silica monolith as the extractant phase holder

Piezoelectric crystal immunosensor for sensitive detection of methamphetamine (stimulant drug) in human urine

Novel fiber coated with β-cyclodextrin derivatives used for headspace solid-phase microextraction of ephedrine and methamphetamine in human urine

Ultra-trace detection of methamphetamine in biological samples using FFT-square wave voltammetry and nano-sized imprinted polymer/MWCNTs -modified electrode

Liquid-phase microextraction combined with high-performance liquid chromatography for the determination of local anaesthetics in human urine

A highly sensitive, simple and speed technique was employed for the determination of brilliant green in fish (Sphyraena jello) and seawater samples by visible spectrophotometry after its extraction and enrichment with chitosan- zinc oxide nanoparticle coupled with dispersive liquid- liquid microextraction. Ultra-trace concentrations of brilliant green were dispersed to organic phase in DLLME method after adding of dispersive solvent and chitosan- zinc oxide nanoparticles. The experimental factors such as amount of chitosan- zinc oxide nanoparticles, concentration of Triton X- 114, type of volume of extraction and dispersive solvents, extraction time, rate and time of centrifugation, volume of sample and pH were investigated to order to enhance of the extraction efficiency. Under optimum extraction condition, volume of chloroform (as extraction solvent) and methanol (as dispersive solvent) were 100.0 µL and 550.0 µL, respectively; amount of chitosan- zinc oxide nanoparticles was 15.0 mg; time of extraction was 4.0 min; rate and time of centrifugation were 3000.0 rpm and 8.0 min, respectively, volume of sample was 8.0 mL, and pH of sample solution was 4.0. After optimizing of the microextraction conditions and instrumental factors, an enrichment factor of 169.0 was achieved. The analytical curve )absorbance vs. concentration( was linear over the range 1.0-200.0 µg/L of brilliant green. The limit of detection and relative standard deviation were 0.3 µg/L and < 6.1 %, respectively. The protocol was successfully employed to the determination of brilliant green in seawater of Chabahar Bay and fish (Sphyraena jello) samples.

The purpose of this study was to evaluate the ability of two amphetamine class screening reagents to exclude ephedrine (EPH), pseudoephedrine (PSEPH), and phenylpropanolamine (PPA) from falsely producing positive immunoassay screening results. The study also sought to characterize the prevalence and concentration distributions of EPH, PSEPH, and PPA in samples that produced positive amphetamine screening results. Approximately 27,400 randomly collected human urine samples from Navy and Marine Corps members were simultaneously screened for amphetamines using the DRI and Abuscreen online immunoassays at a cutoff concentration of 500 ng/mL. All samples that screened positive were confirmed for amphetamine (AMP), methamphetamine (MTH), 3,4-Methylenedioxyamphetamine (MDA), 3,4-Methylenedioxymethamphetamine (MDMA), EPH, PSEPH, and PPA by gas chromatography/mass spectrometry (GC/MS). The DRI AMP immunoassay identified 1,104 presumptive amphetamine positive samples, of which only 1.99% confirmed positive for the presence of AMP, MTH, MDA, or MDMA. In contrast, the online AMP reagent identified 317 presumptive amphetamine positives with a confirmation rate for AMP, MTH, MDA, or MDMA of 7.94%. The presence of EPH, PSEPH, or PPA was confirmed in 833 of the 1,104 samples that failed to confirm positive for AMP, MTH, MDA, or MDMA; all of the 833 samples contained PSEPH. When compared to the entire screened sample set, PSEPH was present in approximately 3%, EPH in 0.9%, and PPA in 0.8% of the samples. The results indicate that cross reactivities for EPH, PSEPH, and PPA are greater than reported by the manufacturer of these reagents. The distribution of concentrations indicates that very large concentrations of EPH, PSEPH, and PPA are common.

Cold-induced aggregation microextraction: A novel sample preparation technique based on ionic liquids

The major reactant ion in conventional ion mobility spectrometry (IMS) is the hydronium ion, H3O+ which is produced in the usual ionization sources such as corona discharge or radioactive sources. Using the hydronium reactant ion, mostly the analytes with proton affinity higher than that of water are ionized. A broader range of compounds can be detected by IMS if other alternative ionization channels, such as charge transfer from NO+, are employed. In this work we introduce a simple and novel method for producing NO+ as the major reactant ion in IMS. This was achieved by adding neutral NO to the corona discharge ionization source. The neutral NO was prepared via an additional discharge in an air stream, flowing into the corona discharge source. A curtain plate was mounted in front of the corona discharge to prevent the influence of the analyte on the production of NO+. Using this technique, the reactant ion could easily and quickly switch between the H3O+ and NO+. The performance of the new source was evaluated by recording ion mobility spectra of test compounds with both H3O+ and NO+ reactant ions.

Urine methamphetamine-to-amphetamine ratio by LC-MS/MS to differentiate methamphetamine use from pharmaceutical impurity in patients prescribed amphetamine.

Methamphetamine (METH) and amphetamine (AMPH) are both abused psychostimulants. Although METH is generally accepted to be more addictive and potent than its analogue AMPH, there are no known neurobiological differences in action between the two drugs that may account for such differences. METH and AMPH were compared to determine potential mechanisms for such differences between the two drugs in order to provide new targets for the treatment of METH addiction. Using in vivo microdialysis on rats, dopamine (DA), DA metabolites, and glutamate (GLU) release in the nucleus accumbens (NAC) and prefrontal cortex (PFC) were measured after administration of 2 mg/kg, IP, of METH or AMPH. Based on the neurochemical differences between METH and AMPH, a locomotor activity study was designed to assess differences in locomotor activation for a range of doses (1-4 mg/kg, IP) of METH and AMPH and after pretreatment with intra-accumbens GLU antagonists. METH and AMPH raised NAC DA levels to a similar degree. In the PFC, both METH and AMPH raised DA levels, but METH was less effective than AMPH. In the NAC, AMPH raised GLU levels but METH did not. In the PFC, METH raised GLU levels but AMPH did not. The locomotor activity dose response curve for METH had a lower peak than that of AMPH. This difference was blocked by pretreatment with either the GLU NMDA antagonist AP5 or the GLU AMPA antagonist DNQX locally in the NAC. This study reveals several previously unknown neurochemical and behavioral differences between METH and AMPH. Based on these results, it is suggested that new pharmacotherapeutic agents that produce augmentations of NAC GLU or PFC DA activity, or perhaps inhibition of PFC GLU activity, may someday be useful for the treatment of METH addiction.

Monolithic silica capillary column extraction of methamphetamine and amphetamine in urine coupled with thin-layer chromatographic detection

Stereoisomeric identification of norephedrine (NE) derived from methamphetamine (MA) or amphetamine (AM) was investigated by SIM-GC/MS assay using the urine of 33 MA abusers and 1 AM abuser. The assay simultaneously identified TFA-derivatized MA and AM metabolites, including AM, p-hydroxyl-MA (p-HMA), and p-hydroxyl-AM (p-HAM). The analysis lasted approximately 43 min, with a signal-to-noise ratio of >or=3 and a detection limit of 50 ng/mL. Among 12 urine samples from different subjects, only the S (+) form of MA and its metabolites (AM, p-HMA, p-HAM) was detected, however, a (1R,2S)-(-)-NE stereoisomer was also identified. Among the urine samples of two subjects, only the R (-) form of MA and its metabolites (AM, p-HMA, p-HAM) was detected, while NE was not detected. Following urinalysis of urine obtained from 19 MA abusers and 1 AM abuser, only the (1R,2S)-(-)-NE stereoisomer was identified, while unmetabolized MA, AM, and their metabolites (p-HMA, p-HAM), showed stereoselective metabolism. Although (1R,2S)-(-)-ephedrine (EP) alone was found in the urine of 1 (S)-(+)-MA user and 1 (S)-(+)- and (R)-(-)-MA user among 33 MA users, it was not present in the urine of the remaining 31 subjects. Therefore, (1R,2S)-(-)-NE was likely not of (1R,2S)-(-)-EP origin and was most likely from (S)-(+)-AM of the MA metabolite. The production ratio of (1R,2S)-(-)-NE to (S)-(+)-AM ranged from 0.01 to 0.25 in MA abusers and was 0.12 in AM abusers.

Miniaturized salting-out liquid–liquid extraction in a coupled-syringe system combined with HPLC–UV for extraction and determination of sulfanilamide