ABSTRACT
Electrospray mass spectrometry coupled to liquid chromatography was utilized to measure two PKC neuronal substrates, B-50/GAP-43 and neurogranin, in single rat brain areas. Aliquots of perchloric acid extracts were directly injected and mass spectra recorded. At elution times of 14.2 and 27.0 min two molecular species of MW 7450 and 23 602 Da were observed. These values are in excellent agreement for the expected MW for rat neurogranin and B-50/GAP-43. The presence of molecular species shifted by 80 mass units in both cases indicates that these proteins are present in phosphorylated forms in cortical and hippocampal extracts.
Subject(s)
Brain/metabolism , Calmodulin-Binding Proteins/chemistry , Membrane Glycoproteins/chemistry , Nerve Tissue Proteins/chemistry , Animals , Calmodulin-Binding Proteins/metabolism , Cell Extracts/chemistry , Chromatography, High Pressure Liquid , Electrophoresis, Polyacrylamide Gel , GAP-43 Protein , Immunoblotting , Mass Spectrometry , Membrane Glycoproteins/metabolism , Molecular Weight , Nerve Tissue Proteins/metabolism , Neurogranin , Perchlorates/pharmacology , Phosphorylation , Protein Kinase C/metabolism , RatsABSTRACT
The three most toxic coplanar PCB 77, 126 and 169 have been identified and quantified at ultra trace levels (0.02-4.8 ng/gdw) in swiss sewage sludge samples applying high resolution capillary gas chromatography (HRGC) and electron impact (EI) as well as negative ion chemical ionization (NCI) mass spectrometry (MS). NCI mass spectra have been dominated by the molecular ion as base peak and virtually no fragmentation has been observed. Detection limits of the planar PCB under single ion monitoring (SIM) conditions have been typically 100 fg for NCI-MS and 1 pg for EI-MS. NCI-MS was the preferred detection method for the determination of very low concentrations of these important contaminants in sewage sludge samples.
ABSTRACT
The in vitro reactions of RNase with different concentrations of glucose or fructose have been studied by means of electrospray mass spectrometry coupled with microcolumn high performance liquid chromatography. The results obtained have shown that, subsequent to the protein glycation, a series of cross-linking products are generated. Their molecular weights demonstrate that severe degradation processes of the proteic substrate takes place after the cross-linking process.
Subject(s)
Ribonucleases/metabolism , Amino Acid Sequence , Animals , Cattle , Glucose/chemistry , Glucose/metabolism , Mass Spectrometry , Molecular Sequence Data , Protein Structure, Secondary , Ribonucleases/chemistryABSTRACT
Difficulties with harmonization of analytical procedures and consequently poor comparability of generated data represent in the Czech Republic the main reason for the delay in issuing of updated legislation for polychlorobiphenyls (PCBs) in foodstuffs. This study draws attention to possible errors (overestimations) that can occur during routine determination of these residues in the fat portion of biotic matrices. We demonstrate the gas chromatographic (GC) conditions under which interfering contaminants such as phthalates and/or chlorinated pesticides can be separated from analytes. Discussion is focused on the advantages and drawbacks of GC with an electron capture detector, GC mass spectrometry and GC with an atomic emission detector. Various approaches used for calculation of PCBs contents are compared.
Subject(s)
Adipose Tissue/chemistry , Drug Residues/analysis , Food Contamination/analysis , Milk/chemistry , Polychlorinated Biphenyls/analysis , Animal Feed , Animals , Cattle , Chromatography, Gas , Czech Republic , Environmental Monitoring , Gas Chromatography-Mass Spectrometry , Mutagens/analysis , Reproducibility of ResultsABSTRACT
The fragrance compounds linalool (1) and linalyl acetate (2) could be detected, identified and quantified (1: 7-9 ng ml-1; and 2: 1-2 ng ml-1 and 4-5 ng ml-1 as free linalool) in blood samples after inhalation in animal experiments (mice) by gas chromatography/mass spectrometry (GC/MS) with chemical ionization (CI) (ammonia); selected ion monitoring (SIM) mode (1: m/z 81, 137 and 154; 2: 47, 57 and 137) and GC/flame ionization detection (FID). The inhalation of these monoterpenes in concentrations of 5 mg l-1 air leads to a significant reduction of the motility of the test animals down to 30-40% with respect to the control group.
Subject(s)
Monoterpenes , Perfume/administration & dosage , Terpenes/administration & dosage , Acyclic Monoterpenes , Administration, Inhalation , Animals , Depression, Chemical , Gas Chromatography-Mass Spectrometry/methods , Mice , Movement/drug effects , Terpenes/bloodABSTRACT
An isocratic ion-pair reversed-phase liquid chromatographic method has been developed for the determination of thirteen nucleotides including cyclic AMP and cyclic GMP. The resolution capability of this method was evaluated successfully using homogenates of octopus retina, the aim being to elucidate the role of nucleotides (particularly ADP and ATP) in the control of oxidative metabolism. To overcome the inherent lack of specificity of ultraviolet detection we used the coupling of liquid chromatography with mass spectrometry, via a thermospray interface, to confirm the identity of the nucleotides of interest in the biological samples.
