Due to the extensive use of antimicrobial agents in human and veterinary medicine, residues of various antimicrobials get into wastewater and, subsequently, surface water. On the one hand, a combination of processes in wastewater treatment plants aims to eliminate chemical and biological pollutants; on the other hand, this environment may create conditions suitable for the horizontal transfer of resistance genes and potential selection of antibiotic-resistant bacteria. Wastewater and surface water samples (Morava River) were analyzed to determine the concentrations of 10 antibiotics and identify those exceeding so-called predicted no-effect environmental concentrations (PNECs). This study revealed that residues of five of the tested antimicrobials, namely ampicillin, clindamycin, tetracycline, tigecycline and vancomycin, in wastewater samples exceeded the PNEC. Vancomycin concentrations were analyzed with respect to the detected strains of vancomycin-resistant enterococci (VRE), in which the presence of resistance genes, virulence factors and potential relationship were analyzed. VRE were detected in 16 wastewater samples (11%) and two surface water samples (6%). The PNEC of vancomycin was exceed in 16% of the samples. Since the detected VRE did not correlate with the vancomycin concentrations, no direct relationship was confirmed between the residues of this antimicrobials and the presence of the resistant strains.
- Klíčová slova
- antimicrobial residues, vancomycin-resistant enterococci (VRE), wastewater,
- Publikační typ
- časopisecké články MeSH
The efficiency of desorption/ionization becomes more critical as the sampled surface area decreases. Desorption electrospray and desorption nanoelectrospray belong to ambient ionizations and enable direct surface analysis including mass spectrometric imaging. Lateral resolution in tens of micrometers was demonstrated for desorption nanoelectrospray previously, but sensitivity of the surface scan can be an issue. For desorption electrospray, the drag force in the source is driven by the flow of used gases and vacuum suction. Ion signal intensity can be improved by controlling the nebulizing gas flow rate or auxiliary pumping of a closed compartment in front of the mass spectrometer inlet. Because nanoelectrospray generates charged droplets without the assistance of a nebulizing gas, only vacuum suction drives the gas flow. In this study, the effect of pressure drop between the atmospheric and evacuated region of a mass spectrometer on the ion signal intensity was investigated for desorption nanoelectrospray. A modification of the commercial inlet was designed. An auxiliary pump was directly connected to an inner compartment of the modified mass spectrometer inlet through a needle valve that enabled the regulation of the reduced pressure. Adjustment of the pressure drop significantly increased signal intensity (more than one order of magnitude in some cases). To a lesser extent, the temperature of a heated capillary (an integral part of the inlet) also influenced the signal intensity. The applicability of desorption nanoelectrospray equipped with pressure regulation was demonstrated by the analysis of synthetic cathinones or a pill of paracetamol. Because pressure in the inlet depends on the diameters of orifices and the power of vacuum systems of mass spectrometers, the effect of the pressure regulation can be different for different instruments. Nevertheless, the presented results confirmed the importance of pressure drop-driven transport for desorption nanoelectrospray efficiency and can encourage its new applications.
- Klíčová slova
- cathinones, desorption nanoelectrospray, mass spectrometry, new psychoactive substances, pressure drop regulation,
- Publikační typ
- časopisecké články MeSH
Distinguishing isomeric representatives of "bath salts", "plant food", "spice", or "legal high" remains a challenge for analytical chemistry. In this work, we used vacuum ultraviolet spectroscopy combined with gas chromatography to address this issue on a set of forty-three designer drugs. All compounds, including many isomers, returned differentiable vacuum ultraviolet/ultraviolet spectra. The pair of 3- and 4-fluoromethcathinones (m/z 181.0903), as well as the methoxetamine/meperidine/ethylphenidate (m/z 247.1572) triad, provided very distinctive vacuum ultraviolet spectral features. On the contrary, spectra of 4-methylethcathinone, 4-ethylmethcathinone, 3,4-dimethylmethcathinone triad (m/z 191.1310) displayed much higher similarities. Their resolution was possible only if pure standards were probed. A similar situation occurred with the ethylone and butylone pair (m/z 221.1052). On the other hand, majority of forty-three drugs was successfully separated by gas chromatography. The detection limits for all the drug standards were in the 2-4 ng range (on-column amount), which is sufficient for determinations of seized drugs during forensics analysis. Further, state-of-the-art time-dependent density functional theory was evaluated for computation of theoretical absorption spectra in the 125-240 nm range as a complementary tool.
- Klíčová slova
- Bath salts, Fourier transform ion cyclotron resonance, Gas phase absorption, Isomeric drugs, Time-dependent density functional theory, VUV absorption spectroscopy,
- MeSH
- chromatografie plynová * MeSH
- isomerie MeSH
- nové syntetické drogy analýza MeSH
- spektrální analýza * MeSH
- stimulanty centrálního nervového systému analýza MeSH
- vakuum MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- nové syntetické drogy MeSH
- stimulanty centrálního nervového systému MeSH
We report the evaluation of several mass spectrometry-based methods for the determination of carisoprodol and meprobamate in samples obtained from the rat brain by in vivo intracranial microdialyis. Among the techniques that aspire to perform analyses without chromatographic separation and thereby increase throughput, chip-based nanoelectrospray ionization and the use of an atmospheric pressure solids analysis probe fell short of requirements because of insufficient detection sensitivity and hard ionization, respectively. Although direct analysis in real time provided the required soft ionization, shortcomings of a tandem mass spectrometry-based assay also included inadequate detection sensitivity and, in addition, poor quantitative reproducibility. Therefore, liquid chromatography coupled with atmospheric pressure chemical ionization tandem mass spectrometry was developed to determine carisoprodol and meprobamate from artificial cerebrospinal fluid as the medium. No desalting and/or extraction of the samples was necessary. The assay, combined with in vivo sampling via intracranial microdialyis, afforded time-resolved concentration profiles for the drug and its major metabolite from the nucleus accumbens region of the brain in rats after systemic administration of carisoprodol. Copyright © 2016 John Wiley & Sons, Ltd.
- Klíčová slova
- LC-MS/MS, atmospheric pressure chemical ionization, atmospheric pressure solids analysis probe, carisoprodol, direct analysis in real time, in vivo intracranial microdialysis, meprobamate, nanoelectrospray ionization,
- MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
- karisoprodol mozkomíšní mok metabolismus MeSH
- lidé MeSH
- meprobamát mozkomíšní mok metabolismus MeSH
- mikrodialýza MeSH
- mozek metabolismus MeSH
- potkani Sprague-Dawley MeSH
- reprodukovatelnost výsledků MeSH
- tandemová hmotnostní spektrometrie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- karisoprodol MeSH
- meprobamát MeSH
- Klíčová slova
- adulteration, dietary supplements, phosphodiesterase-5 inhibitors, tandem mass spectrometry, transmission-mode desorption electrospray ionization, ultrahigh performance liquid chromatography,
- MeSH
- cyklické nukleotidfosfodiesterasy, typ 5 * MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
- hmotnostní spektrometrie MeSH
- inhibitory fosfodiesterasy 5 * MeSH
- potravní doplňky MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- dopisy MeSH
- komentáře MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cyklické nukleotidfosfodiesterasy, typ 5 * MeSH
- inhibitory fosfodiesterasy 5 * MeSH
- MeSH
- chlorid sodný chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
- ionty chemie MeSH
- nanotechnologie metody MeSH
- proteiny analýza chemie MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- Publikační typ
- dopisy MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Názvy látek
- chlorid sodný MeSH
- ionty MeSH
- proteiny MeSH
Atmospheric pressure chemical ionization is known for producing unusual artifacts of the ionization process in some cases. In this work, processes occuring in atmospheric pressure chemical ionization/MS of orotic acid that afforded ions accompanying protonated and deprotonated orotic acid molecules in the spectra were studied. Two processes ran in parallel in the ion source: decarboxylation of neutral orotic acid and collision-induced dissociation of its protonated or deprotonated form. A procedure discerning pre-ionization decomposition and post-ionization dissociation by manipulating ion source parameters was proposed. Experiments with isotopically labeled solvents confirmed ion-molecule reactions of the product of collision-induced dissociation of protonated orotic acid with solvent molecules in the ion source and even under vacuum in the ion trap.
- MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací metody MeSH
- ionty chemie MeSH
- kyselina orotová chemie MeSH
- protony MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vodík-deuteriová výměna MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- ionty MeSH
- kyselina orotová MeSH
- protony MeSH
Chemical warfare agents and their degradation products represent a broad group of compounds with different chemical properties (polarity, volatility, thermostability, etc.). These chemicals often have to be detected and determined in complex matrices and therefore highly efficient separation techniques hyphenated to selective and sensitive detectors play an indispensable role. This review offers an overview of selected papers devoted to the title subject. It cannot be considered as a comprehensive literature compilation but should allow the reader to obtain an insight into the application of separation techniques in the important area of human protection and control of chemical weapons.
- MeSH
- chemické bojové látky analýza izolace a purifikace MeSH
- chemický terorismus MeSH
- chromatografie kapalinová metody MeSH
- chromatografie plynová metody MeSH
- elektroforéza kapilární metody MeSH
- hmotnostní spektrometrie metody MeSH
- lidé MeSH
- monitorování životního prostředí metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- chemické bojové látky MeSH
Chiral analysis is an important task of analytical chemistry. Besides separation techniques, mass spectrometry can be applied in this field. One mass spectrometric approach is based on Cooks' kinetic method. The method was successfully applied in a static system in which the concentration of the analyte as well as the chiral selector solution was constant during the experiment. The application of the kinetic method in dynamic systems (changing concentration of analyte) is presented. Such systems allow the speeding up of the analytical process (flow injection analysis (FIA)) or the use of the kinetic method for chiral detection after liquid chromatographic separation. The influence of the concentration of the components of the chiral selector solution as well as its flow rate on the recognition of enantiomers was evaluated. A new procedure for correction for the differences between ratio of enantiomers in the liquid phase and their observed ratio in the gas phase is also described. A significant improvement in accuracy using this procedure was achieved. Applicability of the method was demonstrated in the analysis of amino acids using FIA as well as HPLC/MS. After an achiral separation of leucine and isoleucine, chiral mass spectrometric detection was successfully used for enantiomeric recognition.
- MeSH
- algoritmy * MeSH
- aminokyseliny chemie MeSH
- hmotnostní spektrometrie metody MeSH
- isomerie * MeSH
- kinetika MeSH
- průtoková injekční analýza metody MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aminokyseliny MeSH
Fumaric acid esters, namely dimethylfumarate, have been used for the treatment of psoriasis for many years. Still, their mode of action is not fully clear. Because addition of nucleophiles to the double bonds of fumarates can occur (Michael analogous addition), a study of the interaction of fumarates with cysteine and cysteine-containing peptides possessing nucleophilic sulfhydryl group was carried out. Experiments were performed in aqueous medium at pH 7.4 and at 37 degrees C to simulate physiological conditions. It was proven by mass spectrometric measurements using an ion-trap and time-of-flight instrument that a covalent bond can form between fumarates and the sulfhydryl group of cysteine or cysteinyl residues in peptides. Structures of the interaction products were elucidated by multistage mass spectrometry applying collision-induced dissociation. Higher reactivity of dimethylfumarate in comparison to monomethylfumarate and fumaric acid was observed.
- MeSH
- atmosférický tlak MeSH
- dermatologické látky chemie MeSH
- dimethyl fumarát MeSH
- fumaráty chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací metody MeSH
- peptidy chemie MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- sulfhydrylové sloučeniny chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- dermatologické látky MeSH
- dimethyl fumarát MeSH
- fumaráty MeSH
- peptidy MeSH
- sulfhydrylové sloučeniny MeSH
