RATIONALE: Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is used for the fast qualitative and quantitative analysis of phosphatidylcholines (PC). Fatty acyl chain lengths and the number of double bonds (DB) affect relative responses of PC; hence the determination of correction factors of individual PC is important for the accurate quantitation. The signal intensity in MALDI-MS strongly depends on the matrix; therefore, the following matrices typically used in lipidomics are studied in the present work: 2,5-dihydroxybenzoic acid (DHB), 1,5-diaminonaphthalene (DAN) and 9-aminoacridine (9AA). METHODS: Series of PC with various fatty acyl chain lengths are synthesized for this study. PC concentrations over two orders of magnitude are studied with MALDI-MS. These experiments provide sets of calibration curves for each of the synthesized PC and the further analysis of parameters of calibration curves is performed. RESULTS: Correction factors for PC decrease with increasing fatty acyl chain length for all matrices. These dependences are steeper for unsaturated PC than for saturated ones. MALDI matrices also have a significant effect on this dependence. The weakest dependence on fatty acyl chain length is found for saturated PC in 9AA. In the case of the other matrices, the effect of fatty acyl chain length on the response is essential for both saturated and unsaturated PC. Calibration curves and parameters of calibration curves for both saturated and monounsaturated PC are fitted by a linear function with regression coefficients decreasing in the order 9AA > DAN > DHB. CONCLUSIONS: Differences in relative responses for PC in MALDI-MS measurements must be taken into account for accurate quantitation. Parameters of calibration curves can be used for the determination of PC concentrations using a single internal standard (IS). This method gives good results for the 9AA matrix, but the reproducibility of measurements for the DHB and DAN matrices is lower and the method can be used for a rough estimation only. These matrices are less convenient for the quantitation of PC.
- MeSH
- fosfatidylcholiny krev chemie MeSH
- lidé MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Differences among lipidomic profiles of healthy volunteers, obese people and three groups of cardiovascular disease (CVD) patients are investigated with the goal to differentiate individual groups based on the multivariate data analysis (MDA) of lipidomic data from plasma, erythrocytes and lipoprotein fractions of more than 50 subjects. Hydrophilic interaction liquid chromatography on ultrahigh-performance liquid chromatography (HILIC-UHPLC) column coupled with electrospray ionization mass spectrometry (ESI-MS) is used for the quantitation of four classes of polar lipids (phosphatidylethanolamines, phosphatidylcholines, sphingomyelins and lysophosphatidylcholines), normal-phase UHPLC-atmospheric pressure chemical ionization MS (NP-UHPLC/APCI-MS) is applied for the quantitation of five classes of nonpolar lipids (cholesteryl esters, triacylglycerols, sterols, 1,3-diacylglycerols and 1,2-diacylglycerols) and the potential of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is tested for the fast screening of all lipids without a chromatographic separation. Obtained results are processed by unsupervised (principal component analysis) and supervised (orthogonal partial least squares) MDA approaches to highlight the largest differences among individual groups and to identify lipid molecules with the highest impact on the group differentiation.
- MeSH
- dospělí MeSH
- kardiovaskulární nemoci krev MeSH
- kohortové studie MeSH
- lidé středního věku MeSH
- lidé MeSH
- lipidy krev chemie klasifikace MeSH
- lipoproteiny krev chemie klasifikace MeSH
- metoda nejmenších čtverců MeSH
- multivariační analýza MeSH
- obezita MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- výpočetní biologie MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ultrahigh-performance liquid chromatography coupled with high-mass-accuracy tandem mass spectrometry (UHPLC-MS-MS) has been used for elucidation of the structures of oxidation products of atorvastatin (AT), one of the most popular commercially available drugs. The purpose of the study was identification of AT metabolites in rat hepatocytes and comparison with electrochemically generated oxidation products. AT was incubated with rat hepatocytes for 24 h. Electrochemical oxidation of AT was performed by use of a three-electrode off-line system with a glassy carbon working electrode. Three supporting electrolytes (0.1 mol L(-1) H2SO4, 0.1 mol L(-1) HCl, and 0.1 mol L(-1) NaCl) were tested, and dependence on pH was also investigated. AT undergoes oxidation by a single irreversible process at approximately +1.0 V vs. Ag/AgCl electrode. The results obtained revealed a simple and relatively fast way of determining the type of oxidation and its position, on the basis of characteristic neutral losses (NLs) and fragment ions. Unfortunately, different products were obtained by electrochemical oxidation and biotransformation of AT. High-mass-accuracy measurement combined with different UHPLC-MS-MS scans, for example reconstructed ion-current chromatograms, constant neutral loss chromatograms, or exact mass filtering, enable rapid identification of drug-related compounds. β-Oxidation, aromatic hydroxylation of the phenylaminocarbonyl group, sulfation, AT lactone and glycol formation were observed in rat biotransformation samples. In contrast, a variety of oxidation reactions on the conjugated skeleton of isopropyl substituent of AT were identified as products of electrolysis.
- MeSH
- biologický transport MeSH
- biotransformace MeSH
- elektrolýza MeSH
- glykoly chemie metabolismus MeSH
- hepatocyty cytologie účinky léků metabolismus MeSH
- hydroxylace MeSH
- koncentrace vodíkových iontů MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- kyseliny heptylové chemie metabolismus MeSH
- laktony chemie metabolismus MeSH
- molekulová hmotnost MeSH
- oxidace-redukce MeSH
- pyrroly chemie metabolismus MeSH
- tandemová hmotnostní spektrometrie MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
