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.

• Klíčová slova
• Aqueous samples, GC–MS/MS analysis, Metabolites, Protozoa, Trimethylsilylation,
• 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
• Názvy látek
• alanin MeSH
• glukosa MeSH
• hexamethylsilazane MeSH Prohlížeč
• kyselina mléčná MeSH
• N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide MeSH Prohlížeč
• organické sloučeniny křemíku MeSH
• trimethylsilylové sloučeniny MeSH

With the increasing number of abused stimulant and psychedelic drugs, along with so called "dance drugs" and "new synthetic drugs" available on the Czech illegal market, there is a need to update methods in toxicological laboratories and therefore it is necessary to develop and optimalize screening and identification procedures for new toxic substances appearing in the laboratory practice. It is well known that relatively popular commercial screening immunoassays have some limits: for instance restricted amount of detectable substances, specificity and sensitivity of detection. Therefore, it is mandatory to combine or complete them with more specific methods based on a different principle. In this paper we have focused on collecting useful analytical data to introduce or complete the system of detection and identification of unknown drugs and their metabolites which can appear in biological samples by using gas chromatography-mass spectrometry (GC-MS) after preparation of relevant acetylated derivatives. The collection of experimental data involves retention indexes and mass spectra of acetylated phenylalkylamines, tryptamines and piperazines and some of their metabolites. These data are fundamental for laboratory diagnostics of drugs of abuse or intoxication and they can be useful for practical application in a number of toxicological laboratories. The mean limit of detection 0.1 ng analyte injected to GC-MS is low enough to allow the method to be successfully applied to real toxicological samples.

• MeSH
• halucinogeny izolace a purifikace   MeSH
• lidé MeSH
• odhalování abúzu drog * MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí * MeSH
• stimulanty centrálního nervového systému izolace a purifikace   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• halucinogeny MeSH
• stimulanty centrálního nervového systému MeSH

Recently developed and validated simple and reliable quantitative method employing ethanol as an internal standard (IS) for GC-MS quantification of volatile compounds in alcoholic products was applied to 36 samples including commercially available world-famous brand spirits from 18 countries and homemade distillates. The GC-MS analyses were performed simultaneously by the suggested approach and official IS method that is prescribed in the legislation of EU and USA. The independent samples t-test was employed to evaluate the statistical difference between the results of these two methods. The test revealed no difference in the results and their repeatability. The main benefits of the suggested method are the elimination of the necessity of manual IS addition and samples density measurement thus making it more economical and productive.

• Klíčová slova
• Alcoholic products, Gas chromatography-mass spectrometry (GC–MS), Internal standard method, Spirit drinks, Volatile compounds quantification,
• MeSH
• alkoholické nápoje analýza   MeSH
• bezpečnost potravin * MeSH
• kvalita jídla * MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí metody   MeSH
• Publikační typ
• časopisecké články MeSH

A new arrangement of the INCAT (inside needle capillary adsorption trap) device with Carbopack X and Carboxen 1000 as sorbent materials was applied for sampling, preconcentration and injection of C6C19n-alkanes and their monomethyl analogs in exhaled breath samples. For the analysis both GC-MS/MS and GC×GC-FID techniques were used. Identification of the analytes was based on standards, measured retention indices and selective SRM transitions of the individual isomers. The GC-MS/MS detection limits were in the range from 2.1 pg for n-tetradecane to 86 pg for 5-methyloctadecane. The GC×GC-FID detection limits ranged from 19 pg for n-dodecane to 110 pg for 3-methyloctane.

• Klíčová slova
• Exhaled breath, INCAT, Monomethylalkanes, Needle trap, n-Alkanes,
• MeSH
• alkany analýza   chemie   MeSH
• dechové testy metody   MeSH
• lidé MeSH
• limita detekce MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí metody   MeSH
• reprodukovatelnost výsledků MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alkany MeSH

A simple analytical workflow is described for gas chromatographic-mass spectrometric (GC-MS)-based chiral profiling of secondary amino acids (AAs) in biological matrices. The sample preparation is carried out directly in aqueous biological sample extracts and involves in situ heptafluorobutyl chloroformate (HFBCF) derivatization-liquid-liquid microextraction of nonpolar products into hexane phase followed by subsequent formation of the corresponding methylamides from the HFB esters by direct treatment with methylamine reagent solution. The (O, N) HFB-butoxycarbonyl-methylamide AA products (HFBOC-MA) are separated on a Chirasil-L-Val capillary column and quantitatively measured by GC-MS operated in selected ion monitoring (SIM) mode. The protocol includes 12 simple pipetting steps and covers the quantitative analysis of 8 L, D pairs of secondary amino acids, including proline, isomeric 3-, 4-hydroxyprolines, pipecolic acid, nipecotic acid, azetidine-2-carboxylic acid, and cis- and trans-5-hydroxy-L-pipecolic acid using 13C5 -L-proline as an internal standard. The individual analytical steps are commented on and explained, with emphasis on the chiral GC-MS analysis of secondary amino acids in human urine, serum, and peptide hydrolysate samples.

• Klíčová slova
• Alkyl chloroformate derivatization, Amino acids, Chiral analysis, GC-MS, Peptide hydrolysates, Quantitative analysis, Secondary amino acids, Serum, Urine,
• MeSH
• aminokyseliny * chemie   analýza   moč   krev   MeSH
• fluorokarbony chemie   MeSH
• formiáty chemie   MeSH
• lidé MeSH
• mikroextrakce kapalné fáze metody   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí * metody   MeSH
• stereoizomerie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny * MeSH
• fluorokarbony MeSH
• formiáty MeSH
• heptafluorobutyl chloroformate MeSH Prohlížeč

Proso millet (Panicum miliaceum) is neglected in human nutrition. Thanks to the composition of the grains, millet is suitable for people with celiac disease and it is also useful in the prevention of cardiovascular diseases. For screening the substances in all plant parts of millet via GC-MS, two varieties, Hanacká Mana and Unicum, were used. Substances from the group saccharides, amino acids, fatty acids, carboxylic acids, phytosterols and others were identified in the roots, leaves, stems, and seeds. The highest level of saccharides was found in the stems (83%); amino acids in the roots (6.9%); fatty acids in the seeds (24.6%); carboxylic acids in the roots (3%), phytosterols in the seeds (10.51%); other substances, such as tetramethyl-2-hexadecenol (1.84%) and tocopherols (2.15%), in the leaves; retinal in the roots (1.30%) and squalene in the seeds (1.29%). Saccharides were the dominant group in all plant parts of proso millet followed by fatty acids. The dominant saccharides in all parts of the millet plant were sucrose, fructose and psicose. On the contrary, turanose, trehalose, glucose and cellobiose belonged to the least represented sugars. Additionally, amyrin, miliacin, campesterol, stigmasterol, β-sitosterol, and others were identified. Varietal variability can be assumed, e.g., in retinal, miliacin or amyrin content.

• Klíčová slova
• GC–MS, amino acid, carboxylic acid, fatty acid, miliacin, proso millet, retinal, saccharide, squalene,
• Publikační typ
• časopisecké články MeSH

A sensitive evidence of trace concentrations of benzodiazepines and their metabolites in urine can be enabled after special sample preparation including enzymatic hydrolysis, special solid phase extraction, silylation and following analysis by gas chromatography with mass spectrometry in electron impact mode. After optimalization of the procedure the extraction recovery values in the range 50-85% are achieved. The scale of retention times with basic mass spectral data are presented for the spectrum of silylated benzodiazepines which can overlap some gaps in the standard toxicological literature up to now available.

• MeSH
• anxiolytika moč   MeSH
• benzodiazepiny MeSH
• lidé MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí * MeSH
• senzitivita a specificita MeSH
• trimethylsilylové sloučeniny moč   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• anxiolytika MeSH
• benzodiazepiny MeSH
• trimethylsilylové sloučeniny MeSH

N-acyl homoserine lactones (N-HLs) are signaling molecules synthesized by gram-negative bacteria to communicate in a process called quorum sensing. Most reported methods for the analysis of N-HLs, which are chiral molecules, do not distinguish between enantiomers. Typical examples include biosensors, liquid chromatography with UV detection, gas chromatography coupled with a mass spectrometer (GC-MS) and liquid chromatography coupled with mass spectrometer (LC-MS). Recently, the production of both D,L-N-HLs have been reported in Vibrio fischeri and Burkholderia cepacia. Concentrations of the D-N-HLs were found at the limit of quantification for the employed method. Therefore, for further studies of the role of the D-N-HLs in bacterial physiology, more sensitive, reliable, and selective analytical methods are necessary. In this work, such comprehensive chiral analytical methods for the identification and determination of 18 N-HLs using solid phase extraction followed by GC-MS/MS and LC-MS/MS analyses were developed. Extraction recoveries for the more hydrophilic C4 N-HLs were <10% of all other N-HLs, thus offering a possible explanation as to their lack of detection in previous studies. The chiral separations of all 18 N-HLs derivatives were accomplished by the complementary GC-MS/MS and LC-MS/MS methods. The limit of detection for LC-MS/MS method was as low as 1 ppb. The limit of detection for the GC-MS/MS method was found to be one to three orders of magnitude higher than the LC-MS/MS method. Due to the high extraction recovery and a preconcentration factor of 100, concentrations as low as 10 ppt can be detected by LC-MS/MS in biological samples. The LC-MS/MS approach provided greater enantioselectivity for the larger, more hydrophobic N-HLs while GC-MS/MS provided better enantioselectivity for the smaller N-HLs.

• Klíčová slova
• Chiral separations, Mass spectrometry, N-acyl homoserine lactones, Quorum sensing, Solid-phase extraction,
• MeSH
• acylbutyrolaktony * MeSH
• chromatografie kapalinová MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• tandemová hmotnostní spektrometrie * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acylbutyrolaktony * MeSH

The potential use of ethanol as an internal standard (IS) for GC-MS analysis was studied. The paper describes the analysis of spirit drinks and other alcoholic products which consist of a mixture of water, ethanol, and volatile compounds. In the suggested method, ethanol was employed as an IS for the common procedure of volatile compounds quantification. A number of standard solutions of nine compounds with different concentrations was prepared in a water-ethanol matrix and measured with GC-MS in the SIM mode. Two possible approaches were suggested to avoid detector saturation during ethanol detection. The first one consisted in using less abundant m/z 47 as quantifiers. These ions mainly correspond to unfragmented heavy ethanol molecules containing one 13 C isotope. The second method consisted in reduction of the voltage of MS electron multiplier. The experiment also included the preparation and subsequent dilution of the standard solution and ethanol with water, which determined the linearity of the modified MS response relative to the ethanol content. Analysis of the obtained results revealed that volatile compounds can be successfully accurately determined with GC-MS by employing ethanol as an IS. Application of the suggested method is not limited to the reported volatile compounds and alcoholic products.

• Klíčová slova
• GC-MS, alcoholic products, ethanol, internal standard, quantification, volatile compounds,
• Publikační typ
• časopisecké články MeSH

Application of gas chromatography-mass spectrometry (GC-MS) can significantly improve trace analyses of compounds in complex matrices from natural environments compared to gas chromatography only. A GC-MS/MS technique for determination of poly-beta-hydroxybutyrate (PHB), a bacterial storage compound, has been developed and used for analysis of two soils stored for up to 319 d, fresh samples of sewage sludge, as well as a pure culture of Bacillus megaterium. Specific derivatization of beta-hydroxybutyrate (3-OH C4:0) PHB monomer units by N-tert-butyl-dimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) improved chromatographic and mass spectrometric properties of the analyte. The diagnostic fragmentation scheme of the derivates tert-butyldimethylsilyl ester and ether of beta-hydroxybutyric acid (MTBSTFA-HB) essential for the PHB identification was shown. The ion trap MS was used, therefore the scan gave the best sensitivity and with MS/MS the noise decreased, so the S/N was better and also with second fragmentation the amount of ions increased compared to SIM. The detection limit for MTBSTFA-HB by GC-MS/MS was about 10(-13) g microL(-1) of injected volume, while by GC (FID) and GC-MS (scan) it was around 10(-10) g microL(-1) of injected volume. Sensitivity of GC-MS/MS measurements of PHB in arable soil and activated sludge samples was down to 10 pg of PHB g(-1) dry matter. Comparison of MTBSTFA-HB detection in natural soil sample by GC (FID), GC-MS (scan) and by GC-MS/MS demonstrated potentials and limitations of the individual measurement techniques.

• MeSH
• Bacillus megaterium chemie   růst a vývoj   MeSH
• glykolipidy analýza   MeSH
• hydroxybutyráty analýza   MeSH
• látky znečišťující půdu analýza   MeSH
• látky znečišťující životní prostředí analýza   MeSH
• odpadní vody analýza   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí metody   MeSH
• polyestery analýza   MeSH
• senzitivita a specificita MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glykolipidy MeSH
• hydroxybutyráty MeSH
• látky znečišťující půdu MeSH
• látky znečišťující životní prostředí MeSH
• odpadní vody MeSH
• poly-beta-hydroxybutyrate MeSH Prohlížeč
• polyestery MeSH