Qualitative and quantitative analysis of ephedrine stimulants in urine by ultra-performance liquid chromatography-tandem mass spectrometry.

RATIONALE: Ephedrine analogues are stimulants that are explicitly required to be quantified and characterized in the Anti-Doping Prohibited List of the World Anti-Doping Agency. Given the difficulty of distinguishing diastereoisomers, the qualitative and quantitative analyses of ephedrine diastereoisomers are difficult. METHODS: An ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS) method was developed to detect five ephedrine analogues, and two pairs of diastereoisomers were identified using this method. The samples were analyzed qualitatively and quantitatively using a tandem mass spectrometer with an electrospray ionization source in multiple reaction detection mode after one-step dilution. RESULTS: The effective detection limits of this method were below 0.5 ng/mL. A matrix effect (range: 83.4% to 102%) was observed in quality control samples. The intra- and inter-day precision was lower than 9.16% and 8.60%, respectively, and the accuracy was within ±8.0%. CONCLUSIONS: The method is efficient, accurate, stable and sensitive, and fully meets the requirements for the detection of ephedrine substances in stimulants.

Sol-gel approach for fabrication of coated anodized titanium wire for solid-phase microextraction: highly efficient adsorbents for enrichment of trace polar analytes.

Nanotubular titania film was prepared in situ on titanium wire and was used as the fiber substrate for solid-phase microextraction (SPME) because of its high surface-to-volume ratio, easy preparation, and mechanical stability. Three different functional coatings, ß-cyclodextrin (ß-CD), ß-cyclodextrin-co-poly(ethylenepropylene glycol) (ß-CD/PEG), and polyethylene glycol (PEG)-based sorbents were chemically bonded to the nanostructured wire surface via sol-gel technology to further enhance the absorbing capability and extraction selectivity. Coupled to gas chromatography-flame ionic detection (GC-FID), the prepared SPME fibers were investigated using diverse compounds. The results indicated that the fibers showed good mechanical strength, excellent thermal stability, and wonderful capacity and selectivity to polar compounds, including polar aromatic compounds, alcohols, and ketones. Combining the superior hydrophilic property of a bonded functional molecule and the highly porous structure of a fiber coating, the prepared PEG-coated SPME fiber showed much higher adsorption affinity to ephedrine and methylephedrine than ß-CD and ß-CD/PEG fibers. The as-established PEG-coated SPME-GC analytical method provided excellent sensitivity (LODs, 0.004 and 0.001 ng mL(-1) for ephedrine and methylephedrine, respectively) and better linear range (0.01-2 000 µg L(-1)). In addition, it has surprising repeatability and reproducibility. Finally, the present approach was used to analyze ephedrine and methylephedrine from real urine samples, and reliable results were obtained.

Development and validation of a hydrophilic interaction liquid chromatography with tandem mass spectrometry method for the simultaneous detection and quantification of etilefrine and oxilofrine in equine blood plasma and urine.

A sensitive hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry method was developed and validated for the simultaneous detection and quantification of etilefrine and oxilofrine in equine blood plasma and urine. The method is highly sensitive and specific with good precision and accuracy. In plasma the limit of detection and limit of quantification are 0.03 and 0.1 ng/mL, respectively, for both analytes. In urine the limit of detection and limit of quantification are 0.3 and 1 ng/mL, respectively, for both analytes. The suitability of the method for doping control analysis in equine species is demonstrated by analyzing postadministration samples collected after a single intravenous administration of 50 mg etilefrine to a standardbred mare. Etilefrine was detected up to 120 h in urine and up to 48 h in plasma. Etilefrine is highly conjugated in equine urine whereas it exists in the free form in equine plasma. Therefore, enzyme hydrolysis prior to sample preparation is recommended for the detection and quantification of etilefrine and oxilofrine in equine urine.

Ultrasound-assisted emulsification microextraction for the determination of ephedrines in human urine by capillary electrophoresis with direct injection. Comparison with dispersive liquid-liquid microextraction.

Ultrasound-assisted emulsification microextraction and dispersive liquid-liquid microextraction were compared for extraction of ephedrine, norephedrine, and pseudoephedrine from human urine samples prior to their determination by capillary electrophoresis. Formation of a microemulsion of the organic extract with an aqueous solution (at pH 3.2) containing 10% methanol facilitated the direct injection of the final extract into the capillary. Influential parameters affecting extraction efficiency were systematically studied and optimized. In order to enhance the sensitivity further, field-amplified sample injection was applied. Under optimum extraction and stacking conditions, enrichment factors of up to 140 and 1750 as compared to conventional capillary zone electrophoresis were obtained resulting in limits of detection of 12-33 µg/L and 1.0-2.8 µg/L with dispersive liquid-liquid microextraction and ultrasound-assisted emulsification microextraction when combined with field-amplified sample injection. Calibration graphs showed good linearity for urine samples by both methods with coefficients of determination higher than 0.9973 and percent relative standard deviations of the analyses in the range of 3.4-8.2% for (n = 5). The results showed that the use of ultrasound to assist microextraction provided higher extraction efficiencies than disperser solvents, regarding the hydrophilic nature of the investigated analytes.

Rapid quantitative determination of ephedra alkaloids in tablet formulations and human urine by microchip electrophoresis.

Microchip electrophoresis with fluorescence detection has been applied for fast separation and determination of ephedra alkaloids in pharmaceutical formulations and body fluids. A custom epifluorescence microscope setup was employed and the compounds were separated within 40 s, allowing the detection of less than 200 ng/L for both analytes. Quantitation of the two stimulants was performed via a derivatization step using FITC without any extraction or preconcentration steps. The effects of different microchip types and excitation light sources were investigated and the method was successfully applied for the analysis of these compounds in tablet formulations, yielding recovery rates from 100.2 to 101.1% and relative standard deviations from 1.5 to 3.4%. Analysis of ephedrines was also carried out with human urine samples at detection limits of 500-1000 ng/L and relative standard deviations from 2.2 to 3.3% using argon ion LIF detection.

Capillary electrophoresis coupled with end-column electrochemiluminescence for the determination of ephedrine in human urine, and a study of its interactions with three proteins.

A tris(2,2-bipyridyl)ruthenium(II) (Ru(bpy)3²âº)-based electrochemiluminescence (ECL) detection coupled with capillary electrophoresis (CE) method has been established for the sensitive determination of ephedrine for the first time. Under the optimized conditions [ECL detection at 1.15 V, 25 mmol/L phosphate buffer solution (PBS), pH 8.0, as running buffer, separation voltage 12.5 kV, 5 mmol/L Ru(bpy)3²âº with 60 mmol/L PBS, pH 8.5, in the detection cell] linear correlation (r = 0.9987) between ECL intensity and ephedrine concentration was obtained in the range 6.0 × 10⁻8-6.0 × 10⁻6 g/mL. The detection limit was 4.5 × 10⁻9 g/mL (S:N = 3). The developed method was successfully applied to the analysis of ephedrine in human urine and the investigation of its interactions with three proteins, including bovine serum albumin (BSA), cytochrome C (Cyt-C) and myoglobin (Mb). The number of binding sites and the binding constants between ephedrine and BSA, Cyt-C and Mb were 8.52, 12.60, 10.66 and 1.55 × 104 mol/L, 6.58 × 10³ mol/L and 1.59 × 104 mol/L, respectively.

Simultaneous determination of eight sympathomimetic amines in urine by gas chromatography/mass spectrometry.

A GC method was developed for the identification and quantitation of eight sympathomimetic amines in urine, i.e., amphetamine, methamphetamine, mephentermine, ephedrine, pseudoephedrine, methylenedioxyamphetamine, methylenedioxymethamphetamine, and methylenedioxyethylamphetamine. Methoxyphenamine was used as the internal standard (IS). The assay is rapid, sensitive, and simple to perform. It involves a liquid-liquid extraction procedure with simultaneous in-solution derivatization of the organic layer with pentafluorobenzoyl chloride (PFB-CI), followed by GC/MS analysis. These derivatives and the IS were extracted from 1 mL alkaline urine into hexane before derivatization with PFB-CI. The organic layer was then removed and evaporated to dryness before dissolution with hexane for GC/MS analysis. Calibration curves for each analyte showed linearity in the range of 25-5000 ng/mL (r2 > or = 0.997). Recoveries ranged from 88 to 99%, with the precision of recoveries typically < or = 5%. The LOD values ranged from 7 to 28 ng/mL, and the LOQ values ranged from 23 to 94 ng/mL. At least four ions were available for each analyte for confirmation of identity by MS.

The use of CE ECL with ionic liquid for the determination of drug alkaloids and applications in human urine.

A new approach for the determination of methylephedrine hydrochloride (ME), thebaine, codeine phosphate (CP), and acetylcodeine (AC) was established by CE-ECL with ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate). The conditions for the CE separation, ECL detection, and the effect of ionic liquid were systematically investigated. Under the optimal conditions, the four analytes were well separated within 8 min using 1-butyl-3-methylimidazolium tetrafluoroborate as additive in the electrophoretic buffer. The concentration detection limits of ME, thebaine, CP, and AC were 2.1 x 10(-8), 1.4 x 10(-7), 6.3 x 10(-8), and 3.6 x 10(-8) mol/L (S/N=3), respectively. The LOQs (S/N=10) in real human urine samples were 7.6 x 10(-7) mol/L for ME, 3.6 x 10(-6) mol/L for thebaine, 6.5 x 10(-7) mol/L for CP, and 4.6 x 10(-7) mol/L for AC, respectively. The recoveries of four alkaloids at different levels in human urine samples were between 90.0 and 103.5%. The developed method was successfully applied to the determination of four drug alkaloids in human urine samples.

The relevance of the urinary concentration of ephedrines in anti-doping analysis: determination of pseudoephedrine, cathine, and ephedrine after administration of over-the-counter medicaments.

This article describes a method for the detection and quantitation of cathine, pseudoephedrine, ephedrine, and methylephedrine in urine, using their deuterated analogues as internal standards and derivatization to form the corresponding trimethylsilyl derivatives after a simple liquid-liquid extraction. The study was designed to evaluate whether the urinary cutoff values set by the World Anti-Doping Agency for the banned ephedrines (cathine >5 microg/mL, ephedrine and methylephedrine >10 microg/mL) can be exceeded after the normal self-administration of common over-the-counter medicaments containing nonbanned ephedrines. The present method, after validation, has been applied on real urine samples obtained from 9 healthy volunteers taking different doses of over-the-counter preparations containing ephedrines. Results obtained from excretion studies show high interindividual differences in the urinary concentrations of both pseudoephedrine and cathine, not dependent on body weight or sex nor, in some instances, on the administered dose. The same typical therapeutic dose of pseudoephedrine (60 mg) produced a urinary concentration of more than 5 microg/mL for cathine and of more than 100 microg/mL for pseudoephedrine in 2 of 9 subjects only. When a dose of 120 mg was administered, cathine concentration exceeded 5 microg/mL in 4 of 7 subject, and also concentrations of pseudoephedrine above 100 microg/mL. After administration of 5 x 120 mg of pseudoephedrine (120 mg administered every 7 days for 5 weeks) to one of the subjects exceeding the urinary threshold values, the urinary concentration of cathine and pseudoephedrine exceeded 5 microg/mL (peak concentration 14.8 microg/mL) and 100 microg/mL (peak concentration 275 microg/mL), respectively. When the same subject took 180 mg of pseudoephedrine, the urinary concentration values were below 5 microg/mL for ephedrine and 100 microg/mL for pseudoephedrine. In the case of ephedrine administration in a sustained-release formulation containing 12 mg of ephedrine, 2 of 3 subjects exceeded the urinary cutoff value of 10 microg/mL. The high interindividual variability is still significant even if the urinary concentration values are adjusted by specific gravity and/or creatinine. These results confirm a high interindividual variability in the urinary concentration of ephedrines after the administration of the same therapeutic dose of a preparation.

Development and validation of an LC-MS/MS method for the quantification of ephedrines in urine.

The objective of this study was to develop a simple and robust LC-MS/MS method for the quantification of ephedrine type substances in urine. Sample preparation consisted of a 10-fold dilution step of the samples into the internal standard solution (ephedrine-d(3), 4 microg/mL in water). Baseline separation of the diastereoisomers norpseudoephedrine-norephedrine and ephedrine-pseudoephedrine was performed on a C8-column using isocratic conditions followed by positive electrospray ionisation and tandem mass spectrometric detection. The mobile phase consisted of 98/2 (H(2)O/ACN) containing 0.1% HAc and 0.01% TFA. Calibration curves were constructed between 2.5 and 10 microg/mL for norephedrine and norpseudoephedrine and 5 and 20 microg/mL for ephedrine, pseudoephedrine and methylephedrine. The bias ranged from -5.5 to 12% for norephedrine, -4.1 to 8.0 % for norpseudoephedrine, 0.3 to 2.1 % for ephedrine, 1.6 to 2.6 % for pseudoephedrine and 2.9 to 5.0 % for methylephedrine. Precision of the method varied between 2.8 and 10.4% for all compounds and the matrix effect was less than 15%. The applicability of the method has been checked by the analysis of 40 urine samples. The results were compared with those obtained with the common GC-NPD method. Results show a good correlation between both methods with correlation coefficients higher than 0.95 for all analytes.

Doping control analysis of metamfepramone and two major metabolites using liquid chromatography-tandem mass spectrometry.

The sympathomimetic agent metamfepramone (2-dimethylamino-1-phenylpropan-1-one, dimethylpropion) is widely used for the treatment of the common cold or hypotonic conditions. Due to its stimulating properties and its rapid metabolism resulting in major degradation products such as methylpseudoephedrine and methcathinone, it has been considered relevant for doping controls by the World Anti-Doping Agency (WADA). The rapid degradation of the active drug complicates the detection of metamfepramone itself but the metabolites methylpseudoephedrine and methcathinone can be monitored, and the finding of the latter in particular allows the inference of a metamfepramone administration. In order to improve sports drug testing procedures, metamfepramone, methylpseudoephedrine and methcathinone were characterized using electrospray ionization-high resolution/high accuracy mass spectrometry, and a method employing liquid chromatography/tandem mass spectrometry was established that allowed the analysis of these three analytes by direct injection of 2 microL of urine specimens. The assay was validated with regard to specificity, lower limits of detection (2-10 ng mL(-1)), intraday and interday precision (3-17%) and ion suppression/enhancement effects. The developed procedure has been used to verify or falsify suspicious signals observed in routine screening procedures based on gas chromatography/mass spectrometry and yielded an adverse analytical finding concerning a metamfepramone administration in an authentic doping control sample. Although the active drug was not detected, the indicative metabolites methylpseudoephedrine and methcathinone were considered sufficient to infer the application of the prohibited drug.

Elimination of ephedrines in urine following administration of a Sho-seiryu-to preparation.

Sho-seiryu-to is one of the most common Traditional Chinese Medicine preparations for the attenuation of colds. Ephedrae Herba is one of the prescriptions of Sho-seiryu-to. The major ingredients of Ephedrae Herba, ephedrines, are banned substances on the World Anti-Doping Agency (WADA) list. The purpose of this study was to investigate the elimination of urinary ephedrines after administering Sho-seiryu-to preparation and to determine the possibility of positive ephedrines test results in urine. Six healthy volunteers took a single 2.5-g dose of concentrated Sho-seiryu-to preparation. All urine was collected for 48 h. The concentrations of urinary ephedrines were analyzed by high-performance liquid chromatography and the elimination half-life of the ephedrines was estimated. The results show that ephedrine and cathine (norpseudoephedrine), the prohibited substances of the WADA, were excreted in the urine after taking a single dose of Sho-seiryuto preparation. The peak concentration of ephedrine was 3.88 +/- 1.87 mg/mL (mean +/- SD), which was lower than the WADA permitted value (10 mg/mL). The estimated elimination half-lives of ephedrine, norephedrine, pseudoephedrine, and norpseudoephedrine following administration of this preparation were 5.3 +/- 1.2, 4.9 +/- 0.9, 4.4 +/- 1.0, and 5.4 +/- 1.8 h, respectively. This study concluded that the urine would not violate the antidoping rules after administering a single dose of Sho-seiryu-to preparation. Nevertheless, an applied multiple-dose study upon administering the preparation for three times per day for three days showed a positive urine ephedrine result (13.7 mg/mL). Athletes should be careful when taking more than a single dose of Sho-seiryu-to preparation.

Simultaneous determination of methylephedrine and pseudoephedrine in human urine by CE with electrochemiluminescence detection and its application to pharmacokeinetics.

A novel method for the determination of ephedra alkaloids (methylephedrine and pseudoephedrine) was developed by electrophoresis capillary (CE) separation and electrochemiluminesence detection (ECL). The use of ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIMBF(4)) improved the detection sensitivity markedly. The conditions for CE separation, ECL detection and effect of ionic liquid were investigated in detail. The two ephedra alkaloids with very similar structures were well separated and detected under the optimum conditions. The limits of detection (signal-to-noise ratio = 3) in standard solution were 1.8 x 10(-8) mol/L for methylephedrine (ME) and 9.2 x 10(-9) mol/L for pseudoephedrine (PSE). The limits of quantitation (signal-to-noise ratio = 10) in human urine samples were 2.6 x 10(-7) mol/L for ME and 3.6 x 10(-7 )mol/L for PSE. The recoveries of two alkaloids at three different concentration levels in human urine samples were between 81.7 and 105.0%. The proposed method was successfully applied to the determination of ME and PSE in human urine and the monitoring of pharmacokinetics for PSE. The proposed method has potential in therapeutic drug monitoring and clinical analysis.

Vapor-phase infrared laser spectroscopy: from gas sensing to forensic urinalysis.

Numerous gas-sensing devices are based on infrared laser spectroscopy. In this paper, the technique is further developed and, for the first time, applied to forensic urinalysis. For this purpose, a difference frequency generation laser was coupled to an in-house-built, high-temperature multipass cell (HTMC). The continuous tuning range of the laser was extended to 329 cm(-1) in the fingerprint C-H stretching region between 3 and 4 microm. The HTMC is a long-path absorption cell designed to withstand organic samples in the vapor phase (Bartlome, R.; Baer, M.; Sigrist, M. W. Rev. Sci. Instrum. 2007, 78, 013110). Quantitative measurements were taken on pure ephedrine and pseudoephedrine vapors. Despite featuring similarities, the vapor-phase infrared spectra of these diastereoisomers are clearly distinguishable with respect to a vibrational band centered at 2970.5 and 2980.1 cm(-1), respectively. Ephedrine-positive and pseudoephedrine-positive urine samples were prepared by means of liquid-liquid extraction and directly evaporated in the HTMC without any preliminary chromatographic separation. When 10 or 20 mL of ephedrine-positive human urine is prepared, the detection limit of ephedrine, prohibited in sports as of 10 microg/mL, is 50 or 25 microg/mL, respectively. The laser spectrometer has room for much improvement; its potential is discussed with respect to doping agents detection.

Simultaneous determination of five toxic alkaloids in body fluids by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

A novel analytical method was developed and validated for the rapid and simultaneous analysis of five toxic alkaloids: Brucine, Strychnine, Ephedrine, Aconitine and Colchicine, in blood and urine using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (HPLC-ESI-MRM) mode. The linear range was 0.05-50.0 ng mL(-1) for Brucine, 0.1-50.0 ng mL(-1) for Strychnine and Ephedrine, 0.01-10.0 ng mL(-1) for Aconitine and Colchicine. The limits of quantification for Brucine, Strychnine, Ephedrine, Aconitine and Colchicine were found to be 0.03, 0.05, 0.20, 0.05, 0.01 ng mL(-1), respectively. The average extraction recoveries in urine ranged from 96.0 to 114.0% and in whole blood were 94.0 to 113.0%. The intra-day and inter-day RSDs were less than 8.3 and 10.6%, respectively. The five alkaloids could be well separated within 7 min in a single run. The established method should be suitable for the determination of trace alkaloids in body fluids.

Liquid-liquid-liquid microextraction followed by HPLC with UV detection for quantitation of ephedrine in urine.

Liquid-liquid-liquid microextraction (LLLME) in combination with HPLC and UV detection has been used as a sensitive method for the determination of ephedrine in urine samples. Extraction process was performed in a homemade total glass vial without using a Teflon ring, usually employed. Ephedrine was first extracted from 3.5 mL of urine sample (pH 12) into a microfilm of toluene/benzene (50:50). The analyte was subsequently back extracted into an acidic microdrop solution (pH 2) suspended in the organic phase. The extract was then injected into the HPLC system directly. An enrichment factor of 137 along with a good sample clean-up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 0.01-50 mg/L with regression coefficient corresponding to 0.998. The LODs and LOQs, based on a S/N of 3 and 10, were 5 and 10 microg/L, respectively. The method was eventually applied for the determination of ephedrine in urine sample after oral administration of 5 mg single dose of drug.

Urinary elimination of ephedrines following administration of the Traditional Chinese Medicine preparation Kakkon-to.

Kakkon-to is one of the most common Traditional Chinese Medicine preparations for the attenuation of colds. Ephedrae Herba is one of the prescriptions of Kakkon-to. The major ingredients of Ephedrae Herba, ephedrines, are banned substances on the World Anti-Doping Agency (WADA) list. The purpose of this study was to investigate the elimination of urinary ephedrines after administering Kakkon-to and to determine the possibility of urinary positive ephedrine test results. Six healthy volunteers took one single dose of 2.5 g Kakkon-to extract granules. The concentrations of urinary ephedrines were analyzed by high-performance liquid chromatography. The result showed that ephedrine and norpseudoephedrine were excreted in the urine after taking one single dose of Kakkon-to. However, the highest amount of ephedrines in urine was ephedrine and the peak concentration was 4.35 +/- 1.82 microg/mL (mean +/- standard deviation), which was lower than the WADA permitted value (10 microg/mL). The estimated elimination half-lives of ephedrine, norephedrine, pseudoephedrine, and norpseudoephedrine following administration of this preparation were: 5.2 +/- 1.2, 4.2 +/- 1.3, 4.2 +/- 0.9, and 6.5 +/- 2.8 h, respectively. This study concluded that the urine would not violate the rule of doping after administering a single dose of Kakkon-to. Nevertheless, a further study on administering the preparation for 3 times per day for 3 days showed a positive ephedrine result. Athletes should be careful when taking more than a single dose of Kakkon-to.

Combining poly (methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction and on-line pre-concentration-capillary electrophoresis for analysis of ephedrine and pseudoephedrine in human plasma and urine.

A method based on poly (methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith microextraction (PMME) and field-enhanced sample injection (FESI) pre-concentration technique was proposed for sensitive capillary electrophoresis-ultraviolet (CE-UV) analysis of ephedrine (E) and pseudoephedrine (PE) in human plasma and urine. The PMME device consisted of a regular plastic syringe (1 mL), a poly (MAA-EGDMA) monolithic capillary (2 cm x 530 microm I.D.) and a plastic pinhead connecting the former two components seamlessly. The extraction was achieved by driving the sample solution through the monolithic capillary tube using a syringe pump, for the desorption step, an aliquot of organic solvent, which normally provided an excellent medium to ensure direct compatibility for FESI in CE, was injected via the monolithic capillary and collected into a vial for subsequent analysis by CZE. The best separation was achieved using a buffer composed of 0.1M phosphate electrolyte (pH 2.5) and 10% acetonitrile (v/v). The combination of both pre-concentration procedures allowed the detection limits of the analytes down to 5.3 ng/mL and 8.0 ng/mL in human plasma and urine, respectively. Excellent method of reproducibility was found over a linear range 50-5000 ng/mL in plasma and urine sample. Plasma and urine samples from volunteers receiving pseudoephedrine have also been successfully analysed.

Capillary electrophoresis with laser-induced fluorescence and pre-column derivatization for the analysis of illicit drugs.

In the current paper, we report the development of a new capillary electrophoresis method using pre-column derivatization and laser-induced fluorescence detection for the determination of ephedrine and amphetamine drugs. Our new method allows for the identification and quantification of six commonly used illicit drugs namely pseudoephedrine, ephedrine, amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, and 3,4-methylenedioxymethylamphetamine, respectively, as well as propafenone (internal standard). Following derivatization with fluorescein isothiocyanate, a total of six amphetamine drugs and the internal standard could readily be separated using a fused-silica 75 micromID x 60 cm length (effective length: 50.2 cm) capillary column. The mobile phase consisted of buffer containing 20mM borate (pH 12, adjusted with sodium hydroxide). Samples were injected in pressure mode with the capillary being operated at 25kV/25 degrees C, and the detection of the derivatized compounds was sought using a laser-induced fluorescence (LIF) detector (lambda(ex)=488 nm and lambda(em)=520 nm), with a run-time of 20 min. The current method was validated with regard to precision (relative standard deviation, RSD), accuracy, sensitivity, linear range, limit of detection (LOD) and limit of quantification (LOQ). In human blood and urine samples, detection limits were 0.2 ngmL(-1), and the linear range of the calibration curves was 0.5-100 ngmL(-1). The intra-day and inter-day precisions were both less than 13.22%.

Rapid simultaneous determination of ephedrines, amphetamines, cocaine, cocaine metabolites, and opiates in human urine by GC-MS.

This paper presents a simple and sensitive chromatographic procedure for the simultaneous determination and quantification of ephedrines, amphetamines, cocaine, cocaine metabolites, and opiates in human urine by gas chromatography-mass spectrometry. This method involves enzyme hydrolysis in the presence of a deuterated internal standard, liquid-liquid extraction, and derivatization with pentafluoropropionic anhydride and pentafluoropropanol. The recovery of each compound averaged at 65.8% or more. The limits of detection determined for each compound by using a 2-mL sample volume ranged from 5 to 50 ng/mL. The calibration curves were linear to 100 ng/mL for all compounds when determined using methamphetamine-d4 and MDMA-d5 as internal standards. This method was successfully applied for the analysis of urine samples suspected to contain intoxicants such as methamphetamine and heroin.