A quantitative LC-ESI single quadrupole MS method for the determination of cortisol (F), cortisone (E), prednisolone (PL), and prednisone (PN) in bovine urine has been developed and validated. After adding flumethasone as internal standard, the samples were subjected to filtration, deconjugation, and solid-phase extraction, while the chromatographic separation was achieved using a Restek Ultra II Allure Biphenyl column with isocratic mobile phase. The analytes were detected after negative electrospray ionization using SIM mode. In order to obtain spectra with maximum intensities of at least one of the three characteristic ions, (M+formate)(-), (M - H)(-), and [(M - H) - CH2O](-), an individual optimization of MS parameters for each corticosteroid was set up. MS data was acquired in the three-ion selected monitoring mode and the ion ratios between chosen diagnostic ions were used in order to increase the specificity. Calibration graphs were linear and the intra-day and intermediate precision was estimated as RSD values which were less than 17%. For F and E, obtained values indicated negligible absolute matrix effects (103% and 98%, respectively). The method was applied to real samples, and basal levels of F and E were preliminarily evaluated, while PL and PN were not detected.

An improved method for determination of 2-dodecylcylobutanone (DCB) in irradiated ground beef patties was developed. This method is based on a head-space solid-phase microextraction (HS-SPME) technique followed by gas-chromatography–mass-spectrometry (GC/MS) detection. SPME conditions were optimised: time and temperature for the adsorption of DCB on the polydimethylsiloxane (PDMS) fiber were set at 60min and 80°C, respectively. A matrix-matched standard calibration in the range 5–150ppb was carried out, using 2-pentylcyclopentanone as internal standard. Linearity (r2=0.9999), repeatability (8.4%), intermediate precision (13.6%), limit of detection (LOD) (1.5ppb), lower limit of quantification (LLOQ) (5ppb) demonstrated that the analytical procedure is fully reliable. The method was applied to irradiated samples in order to evaluate the dose–response effects. The concentration of DCB was quantified in beef patties irradiated at doses as low as 0.5kGy and was linearly increased up to 8kGy.

The objective of the present study was to determine chemical composition, fatty acids profile and hygienic quality of Fatuli, a traditional Italian mountain goat cheese produced from raw milk of Bionda dell'Adamello goats raised semi-extensively in Val Camonica (Northern Italy). The survey was carried out on nine cheeses produced in mountain farms (1700-2000 m) with milk from pasture-fed goats and nine cheeses produced in valley farms (500-900 m) with milk from concentrate-fed goats. Seasonal variations in feeding conditions were responsible of the observed differences especially in fatty acids composition of the samples. Polyunsaturated fatty acids (PUFA) were higher in cheeses from alpine areas as well as n-6/n-3 ratio. Saturated fatty acids (SFA) were higher in cheeses produced in valley farms. Conjugated linoleic acid (CLA), thrombogenicity index (IT) and atherogenicity index (IA) were found lower in Fatuli samples produced in alpine farms with an interesting nutritional effects due to the CLA and n-3 fatty acids role on human health.

A method using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC/MS) was developed and validated for the extraction and quantification of hexanal content in butter (at ngg(-1) level) during storage at 4°C. The variability of hexanal content among seasons of production and the influence of high extraction temperature on ex-novo formation of hexanal were also evaluated. The HS-SPME conditions were optimised and analytical parameters of the method (linearity, accuracy, and precision) demonstrate its usefulness. The reproducibility and accuracy of the quantitative analysis was assured by the use of D(12)-hexanal as internal standard. For the applications, the headspace was extracted using CAR/PDMS fiber for 180min at 4°C. Hexanal contents in samples during all storage period (shelf-life) and from butters produced in different seasons were analysed. Butter samples at the end of shelf-life and samples produced in August showed highest values of hexanal, confirming that the temperature both in storage and distribution phases represents a critical factor to maintain the quality of butter.

BACKGROUND: Solid phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) have been reported as useful techniques for analysing volatile compounds to monitor fish freshness. In this study, SPME/GC/MS was applied to cultured gilthead sea bream and precooked prawn stored in ice for 6 days in order to find possible markers of spoilage. Total volatile basic nitrogen (TVB-N) was also determined as a common index of spoilage.RESULTS: The TVB-N value at the end of the storage period for cultured gilthead sea bream (302.40 +/- 8.50 mg kg(-1)) was within the range of acceptability for edible fish (300-400 mg kg(-1)) but could be considered at the beginning of spoilage. For precooked prawn the TVB-N value at day 6 (863.04 +/- 7.84 mg kg(-1)) was not acceptable for human consumption. SPME/GC/MS identified 30 compounds in cultured gilthead sea bream and 49 compounds in precooked prawn. In particular, 3-methyl-1-butanol, 2-methylbutanal, 3-methylbutanal and 3-hydroxy-2-butanone increased during refrigerated storage both in the two species investigated here and in other species reported elsewhere and could be considered as markers of spoilage.CONCLUSION: This study confirmed that SPME/GC/MS can be considered an efficient method suitable for analysing the volatile compounds of both raw fish and fishery products in order to monitor loss of freshness. (C) 2008 Society of Chemical Industry

The suitability of a portable gas chromatograph equipped with a micro-thermal conductivity detector for the head-space determination of carbon monoxide (CO) in tuna samples is evaluated; CO is estimated after its liberation from tissue by acidic treatment at 70 degrees C. Using the tested technique, the CO contents in untreated and suspected treated samples are analyzed. A limit of detection of approximately 13 ng/g is reached. The results demonstrate that this apparatus has performances similar to more expensive and sophisticated instruments.

The organic volatile compounds produced in oxidized and maleodorous dry salami have been identified. They are: a) in oxidized dry salami: heptanal, hesanal, butyrric, pentanal and isovaleraldehyde; b) in maleodorous dry salami: allil metil sulfide, isovaleraldehyde, butyrric acid.

Spoilage of DFD meat due Aeromonas hydrophila and Hafnia alvei has been described. The alteration is characterized by unpleasant odour (putrid) and by the presence of black spots. The volatile organic substances which are responsable of the putrid odour have been reported.

The nutritional value, the chemical composition and the volatile organic substances (flavouring compounds) of a typical dry salami - which is produced in Montisola, a isle of lseo Lake - have been determined and reported here. Twelve volatile groups of organic substances have been identified terpenes and sulphur compounds are prevalent.

87 volatiles compounds which are present in country style dry salami prepared in the Padania area (Italy) have been identified by mass spectrometry. The profiles of volatile compounds permit the identification and characterization of these dry salami.