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Oscar Quintela - One of the best experts on this subject based on the ideXlab platform.
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Hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC-MS/MS) determination of cocaine and its metabolites benzoylEcgonine, Ecgonine Methyl Ester, and cocaethylene in hair samples
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Oscar Quintela, Elena Lendoiro, Angelines Cruz, Ana Castro, Alfredo Quevedo, Carmen Jurado, Manuel López-rivadullaAbstract:This study reports the development and validation of a method using hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC-MS/MS) for the analysis of cocaine and its metabolites benzoylEcgonine (BE), Ecgonine Methyl Ester (EME), and cocaethylene (CE) in hair samples. Decontamination was performed as follows: Firstly, the aliquot of hair was briefly rinsed with 2 mL dichloromethane, then was washed three times with 10 mL 0.01 M phosphate buffer, pH 6, for 15 min, followed by 2 mL 2-propanol for less than 2 min, and, finally, a last rinse with 2 mL dichloromethane was again done. Cocaine compounds were extracted from 10 mg of hair by incubation with 2 mL 0.1 M HCl at 50 °C for 12 h and purified by solid phase extraction with Oasis MCX cartridges. Analysis was performed by LC-MS/MS using an Atlantis HILIC silica chromatographic column. The method was fully validated. Linearity was established over the concentration range 0.020–10.0 ng/mg for cocaine (COC), 0.010–10.0 ng/mg for BE and CE, and 0.005–2.0 ng/mg for EME, and the correlation coefficients were all >0.99. Extraction efficiency was >70% for all analytes. Limits of detection were 0.0005 ng/mg for CE and 0.001 ng/mg for the other analytes (COC, BE, and EME). Lower limits of quantification were the lowest points of the calibration curves with acceptable accuracy and precision (coefficient of variation ≤20%). Intra- and inter-day imprecision ranged between 1.5% and 9.5% and 0.7% and 12.6%, respectively. Intra- and inter-day inaccuracy ranged from 0.5% to 12.3% and from 0.7% to 7.1%, respectively. With regard to matrix effects, suppression was
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hydrophilic interaction liquid chromatography tandem mass spectrometry hilic ms ms determination of cocaine and its metabolites benzoylEcgonine Ecgonine Methyl Ester and cocaethylene in hair samples
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Oscar Quintela, Elena Lendoiro, Angelines Cruz, Ana Castro, Alfredo Quevedo, Carmen Jurado, Manuel LopezrivadullaAbstract:This study reports the development and validation of a method using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) for the analysis of cocaine and its metabolites benzoylEcgonine (BE), Ecgonine Methyl Ester (EME), and cocaethylene (CE) in hair samples. Decontamination was performed as follows: Firstly, the aliquot of hair was briefly rinsed with 2 mL dichloromethane, then was washed three times with 10 mL 0.01 M phosphate buffer, pH 6, for 15 min, followed by 2 mL 2-propanol for less than 2 min, and, finally, a last rinse with 2 mL dichloromethane was again done. Cocaine compounds were extracted from 10 mg of hair by incubation with 2 mL 0.1 M HCl at 50 °C for 12 h and purified by solid phase extraction with Oasis MCX cartridges. Analysis was performed by LC-MS/MS using an Atlantis HILIC silica chromatographic column. The method was fully validated. Linearity was established over the concentration range 0.020-10.0 ng/mg for cocaine (COC), 0.010-10.0 ng/mg for BE and CE, and 0.005-2.0 ng/mg for EME, and the correlation coefficients were all >0.99. Extraction efficiency was >70% for all analytes. Limits of detection were 0.0005 ng/mg for CE and 0.001 ng/mg for the other analytes (COC, BE, and EME). Lower limits of quantification were the lowest points of the calibration curves with acceptable accuracy and precision (coefficient of variation ≤20%). Intra- and inter-day imprecision ranged between 1.5% and 9.5% and 0.7% and 12.6%, respectively. Intra- and inter-day inaccuracy ranged from 0.5% to 12.3% and from 0.7% to 7.1%, respectively. With regard to matrix effects, suppression was <27.5% in all cases. The method was applied to the analysis of several samples derived from forensic cases.
Ulrike Kohls - One of the best experts on this subject based on the ideXlab platform.
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Body Fluids Using One Isolation Procedure and Liquid Chromatography-Atmospheric-Pressure Chemical-Ionization Mass Spectrometry*
2016Co-Authors: Maciej Bogusz J. T, Rolf-dieter Maier, Klaus-dieter Kriiger, Ulrike KohlsAbstract:Abstract I A method for determining opiate agonists (morphine, morphine-3-glucuronide, morphine-6-glucuronide, 6-monoacetylmorphine, codeine, codeine-6-glucuronide, dihydrocodeine, dihydromorphine, buprenorphine, methadone, tramadol, and ibogaine), cocaine and its metabolites (benzoylEcgonine and Ecgonine Methyl Ester) and lysergic acid diethylamide in serum, blood, urine and other biological matrices is presented. Aliquots (0.5-1.5 mL) of biological fluids were spiked with appropriate deuterated internal standards and extracted using a common solid-phase extraction method (Ct8 cartridges). The extracts were subjected to liquid chromatographic-atmospheric-pressure chemical-ionization mass spectrometric examination using selected ion monitoring procedures. These procedures were developed after analysis of full-scan mass spectra of examined compounds. The extraction method appeared very universal; the recoveries were high for almost all drugs and the extracts were very clean. The procedure was applied for routine forensic casework
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Determination of Common Drugs of Abuse in Body Fluids Using One Isolation Procedure and Liquid Chromatography-Atmospheric-Pressure Chemical-Ionization Mass Spectrometry
Journal of Analytical Toxicology, 1998Co-Authors: Maciej J. Bogusz, Rolf-dieter Maier, Klaus-dieter Krüger, Ulrike KohlsAbstract:I A method for determining opiate agonists (morphine, morphine-3-glucuronide, morphine-6-glucuronide, 6-monoacetylmorphine, codeine, codeine-6-glucuronide, dihydrocodeine, dihydromorphine, buprenorphine, methadone, tramadol, and ibogaine), cocaine and its metabolites (benzoylEcgonine and Ecgonine Methyl Ester) and lysergic acid diethylamide in serum, blood, urine and other biological matrices is presented. Aliquots (0.5-1.5 mL) of biological fluids were spiked with appropriate deuterated internal standards and extracted using a common solid-phase extraction method (Ct8 cartridges). The extracts were subjected to liquid chromatographic-atmospheric- pressure chemical-ionization mass spectrometric examination using selected ion monitoring procedures. These procedures were developed after analysis of full-scan mass spectra of examined compounds. The extraction method appeared very universal; the
Marilyn A Huestis - One of the best experts on this subject based on the ideXlab platform.
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Hierarchical clustering identified three main groups of drug abuse cases.
2013Co-Authors: Elin Lehrmann, Marilyn A Huestis, Carlo Colantuoni, Amy Deep-soboslay, Kevin G. Becker, Ross Lowe, Thomas M. Hyde, Joel E. Kleinman, William J. FreedAbstract:Hierarchical clustering of individual transcriptional profiles from comparisons of drug abuse cases and their individual four best-matched controls identified three main groups of drug abusers: Group I (DA1–18), Group II (DA19–34) and Group III (DA35–42). A summary of toxicology and drug abuse history for each case in the clustering dendrogram indicated cocaine use in a majority of cases, while presence of alcohol in Group I, and opioids and phencyclidine in Group II might underlie differences in Group I and II individuals. Group III cases differed markedly from other cases, which may be related to the absence or low levels of abused drug in most cases, a history of alcohol dependence, or to underlying medical conditions. Insufficient specimen for quantitative analysis of a positive hair test screening is indicated by a parenthesis around the substance name, units are ng/mg, except for cTHC (pg/mg). Abbreviations: 6AM – 6-acetyl morphine, AEME – anhydroEcgonine Methyl Ester, BE - benzoylEcgonine, CE – cocaethylene, COC – cocaine, COD - codeine, cTHC – 11-nor-9-carboxy-tetrahydrocannabinol, EEE – Ecgonine ethyl Ester, EME – Ecgonine Methyl Ester, EtOH – alcohol, g% - g/dL, MDMA – N-Methyl-3,4-Methylenedioxyamphetamine (Ecstasy), MOR – morphine, MTD – methadone, N/A – not available, OXYC – oxycodone, PCP – phencyclidine, THC – delta-9-tetrahydrocannabinol.
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simultaneous analysis of buprenorphine methadone cocaine opiates and nicotine metabolites in sweat by liquid chromatography tandem mass spectrometry
Analytical and Bioanalytical Chemistry, 2011Co-Authors: Marilyn A Huestis, Marta Concheiro, Diaa M ShakleyaAbstract:A liquid chromatography tandem mass spectrometry method for buprenorphine (BUP), norbuprenorphine (NBUP), methadone, 2-ethylidene-1,5-diMethyl-3,3-diphenylpyrrolidine (EDDP), cocaine, benzoylEcgonine, Ecgonine Methyl Ester (EME), morphine, codeine, 6-acetylmorphine, heroin, 6-acetylcodeine, cotinine, and trans-3′-hydroxycotinine quantification in sweat was developed and comprehensively validated. Sweat patches were mixed with 6 mL acetate buffer at pH 4.5, and supernatant extracted with Strata-XC-cartridges. Reverse-phase separation was achieved with a gradient mobile phase of 0.1% formic acid and acetonitrile in 15 min. Quantification was achieved by multiple reaction monitoring of two transitions per compound. The assay was a linear 1–1,000 ng/patch, except EME 5–1,000 ng/patch. Intra-, inter-day and total imprecision were <10.1%CV, analytical recovery 87.2–107.7%, extraction efficiency 35.3–160.9%, and process efficiency 25.5–91.7%. Ion suppression was detected for EME (−63.3%) and EDDP (−60.4%), and enhancement for NBUP (42.6%). Deuterated internal standards compensated for these effects. No carryover was detected, and all analytes were stable for 24 h at 22 °C, 72 h at 4 °C, and after three freeze/thaw cycles. The method was applied to weekly sweat patches from an opioid-dependent BUP-maintained pregnant woman; 75.0% of sweat patches were positive for BUP, 93.8% for cocaine, 37.5% for opiates, 6.3% for methadone and all for tobacco biomarkers. This method permits a fast and simultaneous quantification of 14 drugs and metabolites in sweat patches, with good selectivity and sensitivity.
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urinary excretion of Ecgonine and five other cocaine metabolites following controlled oral intravenous intranasal and smoked administration of cocaine
Journal of Analytical Toxicology, 2010Co-Authors: Michael L Smith, Edward J Cone, Eric T Shimomura, Buddha D Paul, David W Darwin, Marilyn A HuestisAbstract:Urinary excretion of Ecgonine (EC) was compared to that of cocaine, benzoylEcgonine, Ecgonine Methyl Ester and minor metabolites, meta-hydroxybenzoylEcgonine, para-hydroxybenzoylEcgonine, and norbenzoylEcgonine, following controlled administration of oral, intravenous, intranasal, and smoked cocaine. Urine EC concentrations peaked later than all other analytes and had longer detection times than the other minor metabolites. With a 50 ng/mL cutoff concentration and following low doses of 10 to 45 mg cocaine by multiple routes, detection times extended up to 98 h. Maximum concentrations (Cmax) were 6-14 mole % of those for benzoylEcgonine, Cmax increased with dose, time to maximum concentration (Tmax) was independent of dose, and route of administration did not have a significant impact on Cmax or Tmax for metabolites. EC is an analyte to consider for identifying cocaine use due to its stability in urine and long detection times.
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dose related distribution of codeine cocaine and metabolites into human hair following controlled oral codeine and subcutaneous cocaine administration
Journal of Pharmacology and Experimental Therapeutics, 2005Co-Authors: Karl B Scheidweiler, Edward J Cone, Eric T Moolchan, Marilyn A HuestisAbstract:Hair testing for the determination of drug exposure has many useful applications. Drug incorporated into hair can be found for extended periods following drug exposure. There are few controlled drug administration studies investigating drug distribution into human hair. Ten volunteers participated in a 10-week controlled cocaine and codeine administration study while residing in the secure research ward. Weekly hair samples were collected by electric razor. During the low-dose week (week 4), volunteers received 75 mg/70 kg cocaine subcutaneously and 60 mg/70 kg codeine orally on alternating days, a total of three doses for each drug. Similarly, during week 7, volunteers received three doses 150 mg/70 kg cocaine and 120 mg/70 kg codeine. Maximum hair concentrations ( C max ) were found 1 to 3 weeks after low and high doses. Dose-related C max values of cocaine, benzoylEcgonine, Ecgonine Methyl Ester, norcocaine, cocaethylene, and codeine were found following low and high doses. Hair analysis was performed using liquid chromatography tandem mass spectrometry. A positive linear relationship was found between total melanin content of hair and C max of codeine, cocaine, and metabolites following high dosing. This study demonstrated dose-related concentrations of cocaine and metabolites in human hair following controlled cocaine administration. These data are the first demonstrating melanin-related incorporation of cocaine and metabolites into human hair following controlled cocaine administration.
Estela S. Estapé - One of the best experts on this subject based on the ideXlab platform.
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the effect of liquid chromatography eluents and additives on the positive ion responses of cocaine benzoylEcgonine and Ecgonine Methyl Ester using electrospray ionization
International Journal of Mass Spectrometry, 2003Co-Authors: Patrick M. Jeanville, Estela S. Estapé, Ivette Torres-negrón De JeanvilleAbstract:We investigated the effect of common chromatography eluents and additives on the positive ion responses of Ecgonine Methyl Ester (EME), benzoylEcgonine (BZE), and cocaine (COC) using electrospray ionization (ESI). Primarily [M+H]+ ions were observed, although decomposition of EME and COC to ecgonidine Methyl Ester gave a sizable peak at m/z 182.0. The results showed that the sensitivity for the test analytes was greatest in a mobile-phase consisting of a 1:1 mixture of 60% acetonitrile/40% acetone:100 mM ammonium acetate. There was no evidence of a correlation between sensitivity of [M+H]+ ions and solution pH. Adducts derived from addition of ammonium salts and ammonium hydroxide, along with cluster ions were not observed, although cationization did occur for BZE (<1.0–23%). Signal intensities for COC (pKa=8.61) obtained under acidic conditions (pH=2.55–2.80) and basic conditions (pH=9.19–10.02) did not vary, suggesting that mechanisms other than in-solution ionization maybe key in formation of ions by the electrospray process.
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rapid confirmation quantitation of Ecgonine Methyl Ester benzoylEcgonine and cocaine in urine using on line extraction coupled with fast hplc and tandem mass spectrometry
Journal of Analytical Toxicology, 2001Co-Authors: Patrick M. Jeanville, Estela S. Estapé, Ivette Torresnegron, Arturo MartiAbstract:A rapid, rugged, and highly specific assay for the quantitation of cocaine (COC) and especially its primary metabolites benzoylEcgonine (BZE) and Ecgonine Methyl Ester (EME) in human urine has been established. Here, we investigated the use of on-line sample extraction coupled to rapid chromatography systems for tandem mass analysis of COC, EME, and BZE in human urine. Using this method, sample preparation consisted of a sole centrifugation step. Combined extraction and chromatographic run times were < 3.5 min. The lower limits of detection were 0.5 ng/mL, 2.0 ng/mL, and 0.5 ng/mL for EME, BZE, and COC, respectively. Linear calibration curves ranging from 7.5 ng/mL to 1000 ng/mL were produced for the test analytes. Within-day and between-day precision and accuracy of the assay were determined using human urine quality-control specimens at 5, 10, or 15; 150; and 1000 ng/mL. The analyses were performed over the course of five days, rendering %CVs < 10% for EME, BZE, and COC. Percent mean accuracy for the three analytes of 97 to 113% were obtained. Our data suggest that on-line sample extraction coupled with rapid high-performance liquid chromatography-tandem mass spectrometry may be a viable alternative for EME, BZE, and COC analyses in human urine.
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Performance of a pentafluorophenylpropyl stationary phase for the electrospray ionization high-performance liquid chromatography-mass spectrometry-mass spectrometry assay of cocaine and its metabolite Ecgonine Methyl Ester in human urine.
Journal of Chromatography B: Biomedical Sciences and Applications, 2000Co-Authors: Shane R. Needham, Patrick M. Jeanville, Phyllis R. Brown, Estela S. EstapéAbstract:A pentafluorophenylpropyl (PFPP) bonded silica column has been used for the high-performance liquid chromatography–electrospray ionization–mass spectrometry–mass spectrometry assay (HPLC–ESI-MS–MS) of cocaine (COC) and its metabolite, Ecgonine Methyl Ester (EME) in human urine. COC and EME were used as model basic solutes to demonstrate that a PFPP phase yields excellent results for the assay and validation of drugs in biological fluids. The assay was linear over three orders of magnitude (1.0–1000 ng/ml) and precision and accuracy of the assay was 4 and 15%, respectively. The limit of detection (LOD) for COC and EME was 1.6 and 2.8 pg on column, respectively. In addition, only a simple 1:10 dilution of the urine was necessary for the sample preparation procedure thus saving time on a laborious extraction step. The major advantage of the PFPP phase was the enhancement of the ESI-MS signal by providing good retention and good peak shape of COC and EME with a mobile phase of 90% acetonitrile. The MS signal for COC was a factor of 12 times greater on the PFPP phase than on the C18 phase.
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Direct determination of Ecgonine Methyl Ester and cocaine in rat plasma, utilizing on-line sample extraction coupled with rapid chromatography/quadrupole orthogonal acceleration time-of-flight detection
Journal of Pharmaceutical and Biomedical Analysis, 2000Co-Authors: Patrick M. Jeanville, James H. Woods, Theodore J Baird, Estela S. EstapéAbstract:Abstract Our current experiments assess the applicability of on-line sample extraction with coupled rapid chromatography systems to quadrupole orthogonal acceleration time-of-flight (Q-TOF) detection for the quantitative analysis of cocaine (COC), and Ecgonine Methyl Ester (EME) in rat plasma. Experiments were performed on a Q-TOF instrument, operated in the MS/MS mode. Quantitation was achieved utilizing the most prominent parent–daughter transition and internal standard calibration techniques (COC-d 3 : IS). The calibration curves produced for EME and COC ranged from 5.0 to 10 000 and 0.5 to 10 000 ng/ml, respectively. Equations of regression line and correlation coefficients for the pseudo-multiple reaction monitoring (MRM) ion abundance ratio and the corresponding calibration concentrations ( r 2 ) were as follows: y =0.0003+0.0703 x ( r 2 =0.9921) for EME and y =0.0032+0.0035 x ( r 2 =0.9997) for COC. The system repeatability, given as percent coefficient of variation (% CV) of mean peak-area ratios, was assessed using 50 injections of a rat plasma sample from the pharmacokinetic study. The analyses were performed over the course of 5 days, rendering % CVs for EME and COC of 0.73 and 0.58, respectively. This method suggests that on-line sample extraction coupled with fast liquid chromatography/quadrupole orthogonal time-of-flight mass spectrometry may be a viable alternative for quantitative analysis of EME and COC in rat plasma.
Patrick M. Jeanville - One of the best experts on this subject based on the ideXlab platform.
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the effect of liquid chromatography eluents and additives on the positive ion responses of cocaine benzoylEcgonine and Ecgonine Methyl Ester using electrospray ionization
International Journal of Mass Spectrometry, 2003Co-Authors: Patrick M. Jeanville, Estela S. Estapé, Ivette Torres-negrón De JeanvilleAbstract:We investigated the effect of common chromatography eluents and additives on the positive ion responses of Ecgonine Methyl Ester (EME), benzoylEcgonine (BZE), and cocaine (COC) using electrospray ionization (ESI). Primarily [M+H]+ ions were observed, although decomposition of EME and COC to ecgonidine Methyl Ester gave a sizable peak at m/z 182.0. The results showed that the sensitivity for the test analytes was greatest in a mobile-phase consisting of a 1:1 mixture of 60% acetonitrile/40% acetone:100 mM ammonium acetate. There was no evidence of a correlation between sensitivity of [M+H]+ ions and solution pH. Adducts derived from addition of ammonium salts and ammonium hydroxide, along with cluster ions were not observed, although cationization did occur for BZE (<1.0–23%). Signal intensities for COC (pKa=8.61) obtained under acidic conditions (pH=2.55–2.80) and basic conditions (pH=9.19–10.02) did not vary, suggesting that mechanisms other than in-solution ionization maybe key in formation of ions by the electrospray process.
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a catalytic antibody against cocaine attenuates cocaine s cardiovascular effects in mice a dose and time course analysis
International Immunopharmacology, 2001Co-Authors: Richard J Briscoe, Patrick M. Jeanville, James H. Woods, Theodore J Baird, Camilo L Cabrera, Donald W LandryAbstract:The murine monoclonal antibody 15A10 (mAb 15A10), elicited by a transition-state analog for cocaine hydrolysis, has previously been shown to metabolize cocaine in vitro and in vivo. The present experiments were designed to evaluate further the in vivo effectiveness of mAb 15A10 in blocking cardiovascular effects of acute cocaine administration. Balb/c mice were implanted with a femoral artery catheter utilized for mean arterial pressure (MAP) monitoring, and administered intravenous (i.v.) pretreatments of either mAb 15A10 (10, 32, 100 and 300 mg/kg) or vehicle prior to cocaine injection (100 mg/kg, i.p.). A time course analysis for mAb 15A10's effect was also conducted, for which either vehicle or 100 mg/kg mAb 15A10 was infused 1, 3, 10 and 30 days prior to cocaine treatment. During the cardiovascular recording sessions, mice were awake and freely moving within a limited area. Increases in MAP (approximately 25 mm Hg) following cocaine injection were dose-dependently attenuated by mAb 15A10. The antibody-attenuated cocaine-induced increases in MAP at 1- and 3-day pretreatment times, and reduced mortality at some of the time points studied. With 100 mg/kg antibody, plasma cocaine levels were significantly decreased early in the recording session, whereas levels of Ecgonine Methyl Ester increased significantly. Although 10-fold greater quantities of antibody are required to observe significant effects in mouse, compared to our previous studies in rats, the present mouse model provides a convenient paradigm for investigating catalytic and non-catalytic antibodies.
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rapid confirmation quantitation of Ecgonine Methyl Ester benzoylEcgonine and cocaine in urine using on line extraction coupled with fast hplc and tandem mass spectrometry
Journal of Analytical Toxicology, 2001Co-Authors: Patrick M. Jeanville, Estela S. Estapé, Ivette Torresnegron, Arturo MartiAbstract:A rapid, rugged, and highly specific assay for the quantitation of cocaine (COC) and especially its primary metabolites benzoylEcgonine (BZE) and Ecgonine Methyl Ester (EME) in human urine has been established. Here, we investigated the use of on-line sample extraction coupled to rapid chromatography systems for tandem mass analysis of COC, EME, and BZE in human urine. Using this method, sample preparation consisted of a sole centrifugation step. Combined extraction and chromatographic run times were < 3.5 min. The lower limits of detection were 0.5 ng/mL, 2.0 ng/mL, and 0.5 ng/mL for EME, BZE, and COC, respectively. Linear calibration curves ranging from 7.5 ng/mL to 1000 ng/mL were produced for the test analytes. Within-day and between-day precision and accuracy of the assay were determined using human urine quality-control specimens at 5, 10, or 15; 150; and 1000 ng/mL. The analyses were performed over the course of five days, rendering %CVs < 10% for EME, BZE, and COC. Percent mean accuracy for the three analytes of 97 to 113% were obtained. Our data suggest that on-line sample extraction coupled with rapid high-performance liquid chromatography-tandem mass spectrometry may be a viable alternative for EME, BZE, and COC analyses in human urine.
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Performance of a pentafluorophenylpropyl stationary phase for the electrospray ionization high-performance liquid chromatography-mass spectrometry-mass spectrometry assay of cocaine and its metabolite Ecgonine Methyl Ester in human urine.
Journal of Chromatography B: Biomedical Sciences and Applications, 2000Co-Authors: Shane R. Needham, Patrick M. Jeanville, Phyllis R. Brown, Estela S. EstapéAbstract:A pentafluorophenylpropyl (PFPP) bonded silica column has been used for the high-performance liquid chromatography–electrospray ionization–mass spectrometry–mass spectrometry assay (HPLC–ESI-MS–MS) of cocaine (COC) and its metabolite, Ecgonine Methyl Ester (EME) in human urine. COC and EME were used as model basic solutes to demonstrate that a PFPP phase yields excellent results for the assay and validation of drugs in biological fluids. The assay was linear over three orders of magnitude (1.0–1000 ng/ml) and precision and accuracy of the assay was 4 and 15%, respectively. The limit of detection (LOD) for COC and EME was 1.6 and 2.8 pg on column, respectively. In addition, only a simple 1:10 dilution of the urine was necessary for the sample preparation procedure thus saving time on a laborious extraction step. The major advantage of the PFPP phase was the enhancement of the ESI-MS signal by providing good retention and good peak shape of COC and EME with a mobile phase of 90% acetonitrile. The MS signal for COC was a factor of 12 times greater on the PFPP phase than on the C18 phase.
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Direct determination of Ecgonine Methyl Ester and cocaine in rat plasma, utilizing on-line sample extraction coupled with rapid chromatography/quadrupole orthogonal acceleration time-of-flight detection
Journal of Pharmaceutical and Biomedical Analysis, 2000Co-Authors: Patrick M. Jeanville, James H. Woods, Theodore J Baird, Estela S. EstapéAbstract:Abstract Our current experiments assess the applicability of on-line sample extraction with coupled rapid chromatography systems to quadrupole orthogonal acceleration time-of-flight (Q-TOF) detection for the quantitative analysis of cocaine (COC), and Ecgonine Methyl Ester (EME) in rat plasma. Experiments were performed on a Q-TOF instrument, operated in the MS/MS mode. Quantitation was achieved utilizing the most prominent parent–daughter transition and internal standard calibration techniques (COC-d 3 : IS). The calibration curves produced for EME and COC ranged from 5.0 to 10 000 and 0.5 to 10 000 ng/ml, respectively. Equations of regression line and correlation coefficients for the pseudo-multiple reaction monitoring (MRM) ion abundance ratio and the corresponding calibration concentrations ( r 2 ) were as follows: y =0.0003+0.0703 x ( r 2 =0.9921) for EME and y =0.0032+0.0035 x ( r 2 =0.9997) for COC. The system repeatability, given as percent coefficient of variation (% CV) of mean peak-area ratios, was assessed using 50 injections of a rat plasma sample from the pharmacokinetic study. The analyses were performed over the course of 5 days, rendering % CVs for EME and COC of 0.73 and 0.58, respectively. This method suggests that on-line sample extraction coupled with fast liquid chromatography/quadrupole orthogonal time-of-flight mass spectrometry may be a viable alternative for quantitative analysis of EME and COC in rat plasma.
