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The aim of this work was to separate ethanol in an experimental adsorption–desorption device. We focused on concentrating ethanol by adsorption onto granulated activated carbon in its gaseous phase, which was produced by stripping a matrix with different ethanol concentrations (2, 5, 10, and 15% v/v). For adsorption, three kinds of granulated activated carbon (GAC) were used, marked as GAC1, GAC2, and GAC3. The separation product had a higher ethanol concentration than the initial ethanol concentration before the adsorption–desorption process. The enrichment factor was, in the case of the initial ethanol concentration, 2% v/v at the level of 10. With our new adsorption–desorption device, it is possible to achieve a product with an ethanol concentration of 59.0% v/v with stripping, adsorption, desorption, and condensation. To verify the separation efficiency, a real matrix (fermentation broth) was used. The ethanol concentration in the real matrix was, at the beginning of the separation process, 0.65% v/v; after using our separation device, it was 11.35% v/v. Using a real matrix, the enrichment factor was at the level of 18. The main advantage is the use of our new adsorption–desorption device for the continuous separation of ethanol from fermentation broth. A mathematical model was created, based on which it is possible to calculate the ethanol concentration in the product of the separation process with high accuracy. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the content of fatty acids (FAs) in the intramuscular fat of heavy lambs of two breeds: Berrichon du Cher (BE) and Suffolk (SF) in a semi-intensive production system with different nutrition management schemes applied (SI1 and SI2) using gas chromatography. Nutrition differed mainly in a short period before the slaughter: BE/SI1 lambs were fed with hay and concentrates, SF/SI2 lambs grazed and suckled a milk. The samples were taken from the Musculus longissimus dorsi and the analysis of variance with factors of breed/production system (BE/SI1, SF/SI2) and lamb sex (males, females) was used to study the differences in FAs. The content of essential FAs, linoleic acid and a-linolenic acid summed, was higher in SF/SI2 lambs (6.26 g.100 g-1 FAME); this significantly (P < 0.001) differed from BE/SI1 lambs (4.64 g.100 g-1 FAME). The contents of health beneficial FAs (arachidonic, eicosapentaeonic, docosapentaeonic, docosahexaenoic acids) were also higher in SF/SI2 lambs (2.00, 0.59, 0.83, 0.27 g.100 g-1 FAME) and significantly (P < 0.001) differed from BE/SI1 lambs (1.15, 0.30, 0.44, 0.13 g.100 g-1 FAME). The content of conjugated linoleic acid (health beneficial FA as well) was 1.67 g.100 g-1 FAME in SF/SI2 lambs and 1.07 g.100 g-1 FAME in BE/SI1lambs (P < 0.001). The ratio of n-6/n-3 polyunsaturated FAs agreed, whilst the ratio of polyunsaturated/saturated FAs did not agree with the recommended values (found better in SF/SI2 lambs). [ABSTRACT FROM AUTHOR]

Abstract: 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. [ABSTRACT FROM AUTHOR]

A new, rapid, sensitive, robust, and reliable method has been developed for the qualitative analysis of phosphoserine, phosphoethanolamine, phosphoglycerol, and phosphate using gas chromatography with mass spectrometry and two-step trimethylsilylation. The method employs hexamethyldisilazane for silylation of the phosphate and hydroxyl groups in the first phase and bis(trimethylsilyl)trifluoroacetamide for silylation of the less-reactive amino groups in the second phase. This order is of key importance for the method because of the different reactivities of the two reagents and the mechanism of derivatization of the active groups of the analytes. Trimethylsilylated derivatives of the analytes were identified on the basis of their retention times and mass spectra. The probable structures of the major fragments were identified in the spectra of the trimethylsilylated derivatives and characteristic m/ z fragments were selected for each analyte. Fragments with m/ z 73 and 299 occurred in the spectra of all the analytes. The characteristic retention data were employed to calculate the retention indices of the individual silylated phosphorylated substances in the hydrocarbon range C12-C19 for the DB-5ms column. The method was employed to measure the polar fraction of the hydrolysate of the cytoplasmic membrane of Bacillus subtilis. The detection limits vary between 5 μg/mL (trimethylsilylated phosphate) and 72 μg/mL (trimethylsilylated phosphoethanolamine). [ABSTRACT FROM AUTHOR]