N-(3-Phenylprop-2-yn-1-yl)-sulfonamides derived from serine and threonine were synthesized using solid-phase synthesis and subjected to reaction with trimethylsilyl trifluoromethanesulfonate (TMSOTf). In contrast to the previously reported formation of 1,4-oxazepanes, this reaction afforded pyrrolidin-3-ones. A mechanistic explanation for this unexpected outcome is proposed, and the limitations and scope of the rearrangement are outlined.
A simple method for the simultaneous derivatization of carbohydrates, polyols, amines and amino acids using hexamethyldisilazane and N,O-bis(trimethylsilyl)trifluoroacetamide was developed. This method allows the direct derivatization of urine samples without sample pretreatment before derivatization. The method was successfully used for analysis of the selected metabolites in urine samples of healthy individuals and neonates suffering from galactosemia. The limits of detection by positive chemical ionization gas chromatography with tandem mass spectrometry analysis were in the range of 1.0 mgL-1 for mannitol to 4.7 mg/L for glucose.
- MeSH
- algoritmy MeSH
- aminy moč MeSH
- analýza moči MeSH
- dospělí MeSH
- galaktosemie moč MeSH
- kalibrace MeSH
- lidé MeSH
- limita detekce MeSH
- novorozenec MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- polymery analýza MeSH
- reprodukovatelnost výsledků MeSH
- sacharidy moč MeSH
- tandemová hmotnostní spektrometrie MeSH
- trimethylsilylové sloučeniny analýza MeSH
- zmrazování MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
The synthesis and characterization of large-bore silica-based monolithic capillary columns (0.32mm×150mm) are presented. Columns were prepared by acidic hydrolysis of a mixture containing tetramethoxysilane (TMOS) and 1,2-bis(trimethoxysilyl)ethane (BTME) in different molar ratios in the presence of polyethylene glycol and urea. The monoliths were modified by zwitterionic monomer [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl)-ammonium hydroxide via 3-(trimethoxysilyl)propyl methacrylate. Prepared stationary phases were evaluated by scanning electron microscopy and chromatographic separation of nucleobases and their derivatives in the HILIC mode. The best chromatographic results were obtained with the column prepared from the reaction mixture containing BTME and TMOS in a 1:4 molar ratio. The permeability of such column reached 1.68×10(-14)m(2) and the efficiency, expressed as a height equivalent of the theoretical plate, did not exceed 10.5μm for the tested compounds. The columns were successfully applied to HILIC separation of native and labeled oligosaccharides and glycans released from bovine ribonuclease B and human immunoglobulin G.
- MeSH
- chromatografie kapalinová přístrojové vybavení metody MeSH
- ethan analogy a deriváty chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
- hydrofobní a hydrofilní interakce MeSH
- imunoglobulin G metabolismus MeSH
- lidé MeSH
- methakryláty chemie MeSH
- mikroskopie elektronová rastrovací MeSH
- oligosacharidy analýza izolace a purifikace MeSH
- organické sloučeniny křemíku chemie MeSH
- oxid křemičitý chemie MeSH
- ribonukleasy metabolismus MeSH
- skot MeSH
- trimethylsilylové sloučeniny chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A simple two-step method for the derivatization of polar compounds (lactate, alanine, glycerol, succinate and glucose) using hexamethyldisilazane (HMDS) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was developed. This method allows direct derivatization of aqueous samples wihout sample pretreatment. The method was used for the analysis of the metabolites of the unicellular organism Trypanosoma brucei. The limits of detection by GC-MS/MS analysis were in the range of 0.02 mg L(-1) for glucose to 0.85 mg L(-1) for lactate.
- MeSH
- alanin analýza chemie metabolismus MeSH
- glukosa analýza chemie metabolismus MeSH
- kyselina mléčná analýza chemie metabolismus MeSH
- limita detekce MeSH
- organické sloučeniny křemíku chemie MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí metody MeSH
- reprodukovatelnost výsledků MeSH
- trimethylsilylové sloučeniny chemie MeSH
- Trypanosoma brucei brucei chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: The purpose of this study is to develop the gas chromatographic-mass spectrometric method (GC-MS) for screening and semiquantification of drugs and drugs of abuse in human serum. METHOD: GC-MS method after liquid-liquid extraction (LLE) and derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) is presented for screening as well as identification and semiquantification of the most frequently used drugs and drugs of abuse in human serum. RESULTS: Bovine serum spiked with ephedrine (EPHE), 3,4-methylenedioxymethamphetamine (MDMA), guaifenesin (GUAIF), tramadol (TRAM), phenobarbital (PHENO), amitriptyline (AMITR), cocaine (COCA), mirtazapine (MIRTA), dothiepin (DOTH), citalopram (CITAL), clomipramine (CLOMI), bromazepam (BMZPM), diazepam (DZPM), codeine (COD), morphine (MORPH), levomepromazine (LEVO), zolpidem (ZOLP), clozapine (CLOZP), alprazolam (ALPZM) was used for the recovery and repeatability study and for preparation of calibration curves of individual compounds or their TMS derivatives. Recoveries were tested on concentration levels 0.05, 0.1 and 0.5 microg/mL (n=6) and established in range 72.0-98.0%. Repeatabilities expressed as relative standard deviations (RSDs) measured at concentration levels 0.05, 0.1 and 0.5 microg/ mL (n=6) were lower than 10.0%. The calibration curves for analytes or their TMS derivatives were linear in concentration range 0.025-2.000 microg/mL (except of EPHE 2TMS, MDMA TMS, MORPH 2TMS, BMZPM TMS, ALPZM) with correlation coefficients exceeding 0.99. The limit of quantification (LOQ) for analytes used for evaluation study was 0.025 microg/mL (except analytes mentioned above). CONCLUSIONS: The GC-MS method presented here is allowing screening, identification and semiquantification of the most commonly encountered drugs and drugs of abuse in human serum and can be successfully applied to analysis of real samples from clinical and forensic toxicology cases.
- MeSH
- extrakce na pevné fázi MeSH
- fluoracetáty MeSH
- kalibrace MeSH
- kyselina trifluoroctová chemie MeSH
- léčivé přípravky krev MeSH
- lidé MeSH
- odhalování abúzu drog metody MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- poruchy spojené s užíváním psychoaktivních látek krev MeSH
- reprodukovatelnost výsledků MeSH
- trimethylsilylové sloučeniny chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Certain androstane steroids (AS) modulate ionotropic receptors, as do the pregnane steroids. Whereas women produce significant amounts of neuroactive progesterone metabolites, the steroid neuromodulators in men originate mainly from the 3-oxo-4-ene C(19)-steroids, which are converted to their 3alpha- and 3beta-hydroxy-5alpha/5beta-reduced metabolites. The neuromodulating effects of AS prompted us to monitor circulating levels of the steroids to estimate metabolic pathways in the periphery that may influence brain concentrations of AS. Hence, the serum levels of 20 steroids and 16 steroid polar conjugates including 17-oxo- and 17beta-hydroxy-derivatives of 5alpha/beta-androstane-3alpha/beta-hydroxy-androstane steroids were quantified in 15 men (16-62 years of age) using GC-MS. The conjugated AS for the most part reached micromolar concentrations, these being two or three orders of magnitude higher than those of the free steroids. The ratios of conjugates to free steroids were one to two orders of magnitude higher than the values for the corresponding pregnane steroids. This data suggested that conjugation may considerably restrain the transport of free AS from the periphery into the central nervous system.
- MeSH
- androstany chemie krev MeSH
- androstendion chemie MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí metody MeSH
- pregnany krev MeSH
- teplota MeSH
- testosteron MeSH
- tlak MeSH
- trimethylsilylové sloučeniny analýza MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
