A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated for the determination of donepezil in human plasma samples. Diphenhydramine was used as the internal standard. The collision-induced transition m/z 380 --> 91 was used to analyze donepezil in selected reaction monitoring mode. The signal intensity of the m/z 380 --> 91 transition was found to relate l...

The presence of antibiotics in the environment and their subsequent impact on resistance development has raised concerns globally. Hospitals are a major source of antibiotics released into the environment. To reduce these residues, research to improve knowledge of the dynamics of antibiotic release from hospitals is essential. Therefore, we undertook a study to estimate seasonal and temporal va...

the aim of the present investigation was to biotransform the anti-inflammatory compound meloxicam by enzymes present in whole cells of five actinomycete cultures to produce novel bioactive derivatives. among the actinomycetes screened, streptomyces griseus ncim 2622 was found to possess the enzyme system(s) that oxidize meloxicam into two metabolites whereas that present in s. griseus ncim 2623...

Levels of nonsulfated and sulfated tibolone metabolites were determined in plasma, urine, and feces from six ovariectomized, mature female cynomolgus monkeys after a single dose and multiple p.o. doses (including bile) of tibolone using validated gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry assays. In plasma, the predominant nonsulfated metabolite afte...

A rapid LC-MS/MS method was developed and partially validated for the quantitation of montelukast in spiked sheep plasma. A total run time of 1.5 min was achieved using a short monolithic column and employing a rapid gradient. Sample preparation involved protein precipitation with twofold acetonitrile by volume during which a deuterated internal standard (montelukast D-6) was incorporated. The ...

A sensitive and simple liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for the detection of alginate oligosaccharides (AOs) in mouse plasma and urine after oral administration. In an AO mixture, dimer, trimer, and tetramer were detected by LC-MS/MS equipped with an anion-exchange column with extremely high sensitivity. By this method, we detected certain levels of...

New analytical methods for the determination of pesticide residues in wine were introduced and validated. Extraction was performed with sorption active substances on stir bar by gas chromatography-mass spectrometry liquid chromatography-tandem mass spectrometry. The applied practice. A total 77 searched 42 samples from all 3 wine-growing regions Slovenia. fungicides dimethomorph, fludioxonil py...

background: a new microextraction method named dispersive liquid-liquid microextraction (dllme) for determination of chloroform in pool water and blood of swimmers after swimming is described. methods: this method was performed based on coupling dispersive liquid-liquid microextraction (dllme) with gas chromatog­raphy-mass spectrometry (gc-ms). methanol and trichloroethylenes were used as the d...

Mass spectrometry has long been used in clinical laboratories. The first important applications were the use of gas chromatography–mass spectrometry (GC-MS) for drug screening and the diagnosis of organic acid metabolic disorders. More recently liquid chromatography–mass spectrometry [LC-MS; liquid chromatography–tandem mass spectrometry (LC-MS/MS)] has been introduced successfully into clinica...

the aim of this study was to investigate the removal of toluene from air through nano-graphene modified by ionic liquid (ng-il). the batch adsorption experiments in glass bottle of gas chromatography equipped with flame ionization detector (gc-fid) were used. graphene ultrahigh-quality synthesized by substrate-free gas-phase method in a single step and graphene sheets were deposited with ionic-...