A simple high pH liquid chromatography–tandem mass spectrometry method for basic compounds: Application to ephedrines in doping control analysis (original) (raw)
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Determination of ephedrines in urine by gas chromatography–mass spectrometry
Journal of Chromatography B: Biomedical Sciences and Applications, 2001
A selective gas-liquid chromatographic method with mass spectrometry (GC-MS) for the simultaneous confirmation and quantification of ephedrine, pseudo-ephedrine, nor-ephedrine, nor-pseudoephedrine, which are pairs of diastereoisomeric sympathomimetic amines, and methyl-ephedrine was developed for doping control analysis in urine samples. O-Trimethylsilylated and N-mono-trifluoroacetylated derivatives of ephedrines -one derivative was formed for each ephedrine -were prepared and analyzed by GC-MS, after alkaline extraction of urine and evaporation of the organic phase, using 2 d -ephedrine as internal standard. Calibration curves, with r .0.98, ranged from 3.0 to 50 mg / ml depending on the analyte. Validation data (specificity, % RSD, accuracy, and recovery) are also presented.
Journal of Chromatography A, 2000
Different reversed-phase columns for basic analytes were compared for the simultaneous determination of ephedrines in urine, such as LiChrospher 60 RP-Select B, LiChrospher 100 RP18, Hypersil BDS-C18, Inertsil ODS-2, Spherisorb ODS-B and Symmetry Shield RP8. Symmetry Shield was the only column which did not require the use of high concentrations of buffer and triethylamine. With this column, a good separation of the six ephedrines and the internal standard was achieved using 50 mM phosphate buffer-25 mM triethylamine as a mobile phase. Linearity, precision and accuracy were satisfactory for the levels usually found in urine. Due to these all parameters the developed analytical method was found to be suitable for the application in the doping field.
Fast Ephedrine Quantification by Gas Chromatography Mass Spectrometry
Journal of the Brazilian Chemical Society, 2018
Ephedrines are widely used in therapy. Because of their stimulant properties, these substances are relevant in different forensic fields. At present, the state of the art for ephedrines quantification relay based on a liquid chromatography mass spectrometry, mainly because of the dilute-andshoot approach. Notwithstanding, several gas chromatography based methods have already been described, all of them include cleanup steps, with the potential disadvantage of incurring errors and increasing the workload. In this paper, a straightforward method for ephedrine quantification based on gas chromatographic mass spectrometry, without cleanup and based on Doehlert matrix optimization is presented. Only 10 µL of a urine sample is necessary and for N-methyl-N-(trimethylsilyl)trifluoroacetamide/N-methyl-bis-trifluoracetamide derivatives, the intermediate precision was 2.77% for ephedrine, 9.20% for cathine, 8.29% for norephedrine and 4.27% for pseudoephedrine. The limit of detection was 20 ng mL-1 for ephedrine, 30 ng mL-1 for cathine and 40 ng mL-1 for norephedrine and pseudoephedrine.
Journal of Analytical Toxicology, 2010
This study was designed to optimize a method for the identification and quantification of ephedrines in oral fluid (OF) and for its application to subjects taking different doses of pseudoephedrine. Ephedrines use by athletes is banned by World Anti-Doping Agency (WADA), only "in competition" if their concentration in urine exceeds the cutoff limit. The study aimed to establish if there is a correlation in terms of times of elimination and of concentration trends of ephedrine in OF and urine after administration of therapeutic doses of pseudoephedrine to various subjects. Results obtained from excretion studies performed on eight subjects showed reproducible times of disappearance of ephedrines from OF. Pseudoephedrine was generally at low concentrations or undetectable in oral fluid samples 12 h after administration, whereas urine samples collected in the same period of time showed higher ephedrine concentrations and exceeding cutoff values generally between 8 and 24 h after administration of the drug. Within-and between-individual variability was observed in terms of concentrations of pseudoephedrine in OF following the administration of the same dose. Only in the case of sustainedrelease drugs were constant pseudoephedrine concentrations achieved in OF.
Chirality, 2019
Chiral considerations are found to be very much relevant in various aspects of forensic toxicology and pharmacology. In forensics, it has become increasingly important to identify the chirality of doping agents to avoid legal arguments and challenges to the analytical findings. The scope of this study was to develop an liquid chromatography-mass spectrometry (LCMS) method for the enantiomeric separation of typical illicit drugs such as ephedrines (ie, 1S,2R(+)-ephedrine and 1R,2S(−)-ephedrine) and pseudoephedrine (ie, R, R(−)-pseudoephedrine and S,S(+)-pseudoephedrine) by using normal phase chiral liquid chromatography-high-resolution mass spectrometry technique. Results show that the Lux i-amylose-1 stationary phase has very broad and balancing-enantio-recognition properties towards ephedrine analogues, and this immobilized chiral stationary phase may offer a powerful tool for enantio-separation of different types of pharmaceuticals in the normal phase mode. The type of mobile phase and organic modifier used appear to have dramatic influences on separation quality. Since the developed method was able to detect and separate the enantiomers at very low levels (in pico grams), this method opens easy access for the unambiguous identification of these illicit drugs and can be used for the routine screening of the biological samples in the antidoping laboratories.
Analytica Chimica Acta, 2006
A new liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) (n) ion trap method for the determination of corticosteroids in urine has been developed and validated. Some anabolic agents, such as epitrenbolone, trenbolone, 2-hydroxymethylformebolone, tetrahydrogestrinone, gestrinone and formoterol were included in the LC-ESI-MS method. Matrix interference, specificity, identification capability, carry over and robustness were estimated as validation parameters. Recoveries ranged from 74 to 113% at the minimum required performance limit (MRPL), which is 30 ng mL −1 for corticosteroids and 10 ng mL −1 for anabolic agents. Methods for the confirmation and quantification of norpseudoephedrine, ephedrine, methylephedrine, salbutamol, morphine and morphine glucuronide were also developed and validated and in order to minimize analysis time, direct urine injection was used. These methods proved to be specific, accurate and precise across a calibration range for each substance since matrix interference, specificity, carry over, within and between run precision, limit of detection, limit of quantification, intermediate precision and uncertainty were estimated.
Journal of Chromatography A, 2012
The separation of highly basic solutes is an ongoing challenge, especially in achieving suitable retention and peak shapes for compounds such as ephedrines that have both high pK a values (≥9.3) and low lipophilicity (log P ≤ 1.74). In this study we investigate the application of HILIC as a potential alternative approach for the fast separation of the ephedrines phenylpropanolamine, cathine, ephedrine, pseudoephedrine and methylephedrine in doping control analysis. Using sub-2 m bare silica bridgedethylene hybrid (BEH) HILIC material, we evaluate the effects of organic modifier, buffer pH and concentration and column temperature on the retention and selectivity of these compounds. Highly symmetrical peak shapes for all ephedrines were achieved under HILIC conditions (A s0.1 ≤ 1.1). We also compare the kinetic performance of the optimised HILIC separation with a previously developed high pH reversed-phase approach. van Deemter curves and kinetic plots for the two approaches are constructed and illustrate the kinetic benefits of HILIC over the reversed-phase approach. Improved mass transfer characteristics and enhanced diffusion with HILIC offers lower C-term coefficients of 1.46 and 5.68 for ephedrine with HILIC and RPLC, respectively.
Journal of analytical …, 2011
This study established a simultaneous screening method based on solid-phase extraction and liquid chromatography-tandem mass spectrometry (LC-MS-MS) for the detection of 23 stimulants and 23 diuretics in human urine. An electrospray ionization source and multiple reaction monitoring were used for data acquisition. All stimulants and diuretics were separated in less than 12.52 min. The limits of detection were in the range of 25-500 ng/mL for stimulants and 25-125 ng/mL for diuretics. To evaluate the performance of this method, urine samples were collected from 1627 athletes in Taiwan, and 7 positive samples were found. This LC-MS-MS method not only meets the minimum required performance limits set by the World Anti-Doping Agency but also provides a fast way to analyze the authentic urine samples in doping control laboratories.
Journal of Pharmaceutical and Biomedical Analysis, 2002
A simple isocratic reversed-phase high performance liquid chromatograghic method for the separation of pseudoephedrine and its related compounds in pharmaceutical formulations is described. The separation is achieved in less than 35 min on a C-18 column (4.6 mm I.D. )/25 cm length, 5-mm particle size) using a mobile phase consisting of a mixture of ammonium acetate and methanol. The results described in this report demonstrate that the method is sensitive and selective. Structural elucidation of two new pseudoephedrine degradation products is described. On the basis of structural analysis by liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-nuclear magnetic resonance spectroscopy (LC-NMR), the two newly elucidated degradation products were identified to be 2-(carboxyamino)propiophenone (molecular ion of m /z 0/194) and 2-formyl-2-(methylamino)-acetophenone (molecular ion of m /z 0/178). #
JPC – Journal of Planar Chromatography – Modern TLC, 2020
Drug abuse is a global menace in the society. Strict measures are planned and effectuated to dismantle this crime yet a large number of cases of narcotics drugs are seized and referred to forensic science laboratories for analysis. Over the past few years, the misuse of precursor chemicals has increased substantially. Examination of these precursor chemicals, especially ephedrine and its analogues, is a major task for forensic analysts. Though gas chromatography-mass spectrometry (GC-MS) is a well-established technique, it dwindles in the identification of the analogues of ephedrine as they have similarity in molecular weight and structure. The analysis involves timeconsuming extraction and derivatization process in sample preparation when used for the identification of isomers. The present paper describes a use of high-performance thin-layer chromatography coupled with mass spectrometry (HPTLC-MS) for the purpose. This technique requires minimum sample preparation; it is a quick and easy methodology with no derivatization and gives a conclusive result for the separation and identification of ephedrine analogues. The drug samples were dissolved in methanol and spotted on Si 60 F 254 thin-layer chromatography (TLC) plate. Good separation of ephedrine from a mixture of ephedrine, pseudoephedrine, and phenylpropanolamine was achieved using the solvent system n-butyl acetate-acetone-n-butanol-5 M ammonia-methanol (4:2:2:1:1, v/v). The separated spot on the TLC was subjected to MS, which identified ephedrine with confirmation.