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High-performance Liquid Chromatography/tandem Mass Spectrometry (high-performance + liquid_tandem_mass_spectrometry)
Selected AbstractsHigh-performance liquid chromatography/tandem mass spectrometry for the quantitative analysis of a novel taxane derivative (BAY59-8862) in biological samples and characterisation of its metabolic profile in rat bile samplesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2001Cristina Sottani A sensitive, specific, accurate and reproducible high-performance liquid chromatography (HPLC) analytical method was developed and validated for the quantification of the novel oral taxane analogue BAY59-8862 in mouse plasma and tissue samples. A fully automated solid-phase extraction procedure was applied to the plasma after internal standard (IS) addition, with only 0.2,mL volume of the sample loaded on a CN-Sep-pak cartridge. In the case of the tissues a very simple acetonitrile extraction was used to recover BAY59-8862 and its internal standard from liver. The procedure for the quantification of BAY59-8862 and its IS (IDN5127) is based on high-performance liquid chromatography/ion spray-tandem mass spectrometry, operating in selected ion monitoring mode. The retention times of BAY and IS were 7.21 and 10.36,min, respectively. In both plasma and tissue specimens the assay was linear in the range 50,5000,ng/mL (ng/g). The overall precision and accuracy were assessed on three different days. The results for plasma were within 6.1% (precision) and between 99 and 112% (accuracy), and for the liver samples within 7.3% and between 104 and 118%, respectively. The LOD was 5,ng/mL and 20,ng/g in the plasma and liver, respectively. In addition, the biliary excretion of the compound in rats was studied. The study showed that an oxidative chemical reaction was the preferred metabolic pathway for biliary excretion, and two sets of mono- and dihydroxylated metabolites were detected by LC/ISP-MS/MS experiments. With this method, BAY59-8862 pharmacokinetic was determined in mice. The combined results demonstrate that the methodology can be considered a valid approach to conduct pharmacokinetic and metabolic studies during preclinical and clinical investigations. Copyright © 2001 John7 Wiley & Sons, Ltd. [source] Measurement of caffeine and five of the major metabolites in urine by high-performance liquid chromatography/tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2005Allan Weimann Abstract Analysis of caffeine and its metabolites is of interest with respect to caffeine exposure, for kinetic and metabolism studies and for opportunistic in vivo estimation of drug metabolizing enzyme activity in humans and animals. For the latter, analysis is usually done by high-performance liquid chromatography (HPLC) with UV detection. However, this method is close to the detection limit for certain of the metabolites and requires very long chromatography, 30,60 min. We have developed a fast method for the quantification of caffeine and its metabolites 1-methylxanthine, 1-methyluric acid, 1,7-dimethyluric acid, 5-acetylamino-6-amino-3-methyluracil (AAMU) and 5-acetylamino-6-formylamino-3-methyluracil (AFMU) by HPLC tandem mass spectrometry (MS/MS) in urine that requires only its dilution with buffer and centrifugation before injection into the HPLC/MS/MS system. The chromatography lasts 7 min and is followed by 4.5 min for re-equilibration of the HPLC column, giving a total analysis time of 11.5 min. The method provides a great sensitivity improvement with detection limits for all analytes ,25 nM in real samples. Also, the analysis provides much improvement in capacity to ,125 samples per 24 h. Intra- and inter-day coefficients of variation of a single analysis are <6.5% for all the analytes. The inter-day coefficient of variation of duplicate analyses is <4.8% for all analytes. The method is automated, including automated integration, and it is fast, robust and suitable for large-scale investigations in humans and animals. Copyright © 2005 John Wiley & Sons, Ltd. [source] Analysis of electrochemical degradation products of sulphonated azo dyes using high-performance liquid chromatography/tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2006Dana Van, rková Electrochemical treatment of wastewaters containing azo dyes in the textile industry is a promising approach for their degradation. The monitoring of the course of the decomposition of azo dyes in wastewaters is essential due to the environmental impact of their degradation products. In this work, aqueous solutions of a simple azo dye with a low molecular weight (C.I. Acid Yellow 9) and more complex commercial dye (C.I. Reactive Black 5) were electrochemically treated in a laboratory-scale electrolytic cell in sodium chloride or ammonium acetate as supporting electrolytes. Ion-pairing reversed-phase high-performance liquid chromatography coupled with negative-ion electrospray ionization mass spectrometry is applied for the identification of electrochemical degradation products. In addition to simple inorganic salts, the formation of aromatic degradation products obtained due to the cleavage of azo bonds and further degradation reactions is shown, as well as chlorination where sodium chloride is the supporting electrolyte. Degradation mechanisms are suggested for the treatment with sodium chloride as the supporting electrolyte. Copyright © 2006 John Wiley & Sons, Ltd. [source] Separation of a BMS drug candidate and acyl glucuronide from seven glucuronide positional isomers in rat plasma via high-performance liquid chromatography with tandem mass spectrometric detectionRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2006Y.-J. Xue A high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for the determination of a BMS drug candidate and its acyl glucuronide (1- O - , glucuronide) in rat plasma. A 50-µL aliquot of each plasma sample was fortified with acetonitrile containing the internal standard to precipitate proteins and extract the analytes of interest. After mixing and centrifugation, the supernatant from each sample was transferred to a 96-well plate and injected into an LC/MS/MS system. Chromatographic separation was achieved isocratically on a Phenomenex Luna C18, 3,mm,×,150,mm, 3,µm column. The mobile phase contained 0.075% formic acid in 70:30 (v/v) acetonitrile/water. Under the optimized chromatographic conditions, the BMS drug candidate and its acyl glucuronide were separated from its seven glucuronide positional isomers within 10,min. Resolution of the parent from all glucuronides and acyl glucuronide from its positional isomers was critical to avoid their interference with quantitation of parent or acyl glucuronide. Detection was by positive ion electrospray MS/MS on a Sciex API 4000. The standard curve, which ranged from 5 to 5000,ng/mL, was fitted to a 1/x2 weighted quadratic regression model for both the BMS drug candidate and its acyl glucuronide. Whole blood and plasma stability experiments were conducted to establish the sample collection, storage, and processing conditions. The validation results demonstrated that this method was rugged and repeatable. The same methodology has also been used in mouse and human plasma for the determination of the BMS drug candidate and its acyl glucuronide. Copyright © 2006 John Wiley & Sons, Ltd. [source] Matrix-assisted laser desorption/ionization imaging mass spectrometry for direct measurement of clozapine in rat brain tissueRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2006Yunsheng Hsieh Matrix-assisted laser desorption/ionization hyphenated with quadrupole time-of-flight (QTOF) mass spectrometry (MS) has been used to directly determine the distribution of pharmaceuticals in rat brain tissue slices which might unravel their disposition for new drug development. Clozapine, an antipsychotic drug, and norclozapine were used as model compounds to investigate fundamental parameters such as matrix and solvent effects and irradiance dependence on MALDI intensity but also to address the issues with direct tissue imaging MS technique such as (1) uniform coating by the matrix, (2) linearity of MALDI signals, and (3) redistribution of surface analytes. The tissue sections were coated with various matrices on MALDI plates by airspray deposition prior to MS detection. MALDI signals of analytes were detected by monitoring the dissociation of the individual protonated molecules to their predominant MS/MS product ions. The matrices were chosen for tissue applications based on their ability to form a homogeneous coating of dense crystals and to yield greater sensitivity. Images revealing the spatial localization in tissue sections using MALDI-QTOF following a direct infusion of 3H-clozapine into rat brain were found to be in good correlation with those using a radioautographic approach. The density of clozapine and its major metabolites from whole brain homogenates was further confirmed using fast high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) procedures. Copyright © 2006 John Wiley & Sons, Ltd. [source] Development of a low volume plasma sample precipitation procedure for liquid chromatography/tandem mass spectrometry assays used for drug discovery applicationsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2005Xiaoying Xu The demand for high sensitivity bioanalytical methods has dramatically increased in the drug discovery stage; in addition, there has been a growing trend of reducing the sample volume that is required for these assays. A sensitive high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) procedure has been developed and tested to meet these needs. The assay requires only a low plasma sample volume (10,µL) and employs a protein precipitation procedure using a 1:6 plasma/acetonitrile ratio. The supernatant is injected directly into the LC/MS/MS system using the selected reaction monitoring (SRM) procedure for detection. A generic HPLC gradient based on a methanol/water mobile phase with a flow rate set to 0.8,mL/min was used. The test method showed very good linearity between 0.1,1000,ng/mL (R2,=,0.9737), precision (%RSD,=,6,9), accuracy (%RE,=,,2) and reproducibility (%RSD,=,11). A drug discovery IV/PO study was assayed using both the new low volume method and our standard volume (50,µL) method. The correlation of the two sets of data from the two methods was excellent (R2,=,0.9287). This new assay procedure has been successfully used in our laboratory for over 100 different rat or mouse discovery PK studies. Copyright © 2005 John Wiley & Sons, Ltd. [source] Determination of abamectin in soil samples using high-performance liquid chromatography with tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2004Bobby N. Brewer Abamectin, which is comprised of a mixture of avermectins B1a and B1b, is a natural pesticide used as an anti-parasitic agent in livestock, ornamental, and agricultural crops, which can potentially be transported to aquatic systems. These compounds are highly toxic to both aquatic vertebrates and invertebrates at low concentrations in water. This investigation developed high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) techniques to support automated extraction by an accelerated solvent extraction (ASE®) system and chromatographic techniques to measure residues of avermectins in complex soil samples. HPLC along with atmospheric pressure chemical ionization (APCI) MS/MS was used for separation and determination of avermectin isomers in soil samples. Average method recovery for abamectin by UV was 91%, while detection by MS/MS resulted in a 68% recovery for abamectin. Individual method recoveries by MS/MS were 53.6% for avermectin B1a and 36.8% for avermectin B1b. The use of tandem technology eliminated matrix interferences and resulted in an approximately eight-fold increase in sensitivity. Copyright © 2004 John Wiley & Sons, Ltd. [source] Validation of a real-time monitoring method for aniline in freshwater by high-performance liquid chromatography on porous graphitic carbon/electrospray ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2004Raphaël Delépée Aniline is an anthropogenic organic compound widely used in polymer, rubber, pharmaceutical and dye industries but also used in biodegradability assays of chemical compounds as a positive biodegradation standard. By the two approaches, the rapid determination of aniline is necessary because of the high toxicity of aniline on hemoglobin. A high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) method for the determination of aniline in water is described here. This method, using benzylamine as internal standard, was validated. No time-consuming sample preparation was needed. A rapid separation (7,min between two chromatographic runs) of aniline and benzylamine was performed on a Hypercarb porous graphitic carbon column using a gradient of methanol and 100,mM formic acid. The obtained limits of detection and quantification were 10 and 1,ng/mL, respectively. The response for aniline was quadratic. We show that this problem could be circumvented by showing that the [calculated concentration,=,f(introduced concentration)] function was linear. The linearity range was 10,1000,ng/mL. An example of an application consisting of an aniline 42-day degradation kinetic in water was demonstrated. Copyright © 2004 John Wiley & Sons, Ltd. [source] Determination of lamivudine/stavudine/efavirenz in human serum using liquid chromatography/electrospray tandem mass spectrometry with ionization polarity switchBIOMEDICAL CHROMATOGRAPHY, Issue 6 2002Bin Fan A high-performance liquid chromatography/tandem mass spectrometry (LC-MS-MS) method with ionization polarity switch was developed and validated in human serum for the determination of a lamivudine (3TC)/stavudine (d4T)/efavirenz combination HIV therapy. Solid phase extraction (SPE) was used to extract these anti-HIV drugs and internal standard aprobarbital. A gradient mobile phase consisting of acetonitrile and 20,mM ammonium acetate buffer with pH adjusted to 4.5 using glacial acetic acid was utilized to separate these drugs on a hexylsilane column (150,×,2.0,mm i.d.). The total run time between injections was 18,min. The precursor and major product ions of these drugs were monitored on a triple quadrupole mass spectrometer in the multiple reactions monitoring (MRM) mode. Ionization polarity was switched in the middle of the LC run allowing these anti-HIV drugs with different physicochemical properties to be detected simultaneously. The effect of ion suppression from human serum was studied and no interference with the analysis was noted. The method was validated over the range of 1.1,540,ng/mL for 3TC, 12.5,6228,ng/mL for d4T and 1.0,519,ng/mL for efavirenz. The method was shown to be accurate, with intra-day and inter-day accuracy less than 14.0% and precise, with intra-day and inter-day precision less than 13.1%. The extraction recoveries of all analytes were higher than 90%. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||