Silvia Soncin

A headspace solid-phase microextraction gas-chromatographic mass-spectrometric method (HS-SPME–GC/MS) to quantify hexanal in butter during storage as marker of lipid oxidation

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.

Different Fibres for the Analysis of Volatile Compounds in Processed Meat Products by Solid Phase Micro-Extraction (SPME)

L.M. Chiesa1,∗, S. Soncin1, P.A. Biondi2, P. Cattaneo1 and C. Cantoni1 1Laboratory of Food Inspection, Department of Veterinary Sciences and Technologies for Food Safety, Faculty of Veterinary Medicine, University of Milan, Milan, Italy; 2Laboratory of Food Biochemistry, Department of Veterinary Sciences and Technologies for Food Safety, Faculty of Veterinary Medicine, University of Milan, Milan, Italy ∗Correspondence: E-mail: luca.chiesa@unimi.it

Determination of styrene content in gorgonzola PDO cheese by headspace solid phase micro-extraction (HS-SPME) and gas-chromatography mass-spectrometry (GC-MS).

Control of the composition of products that are intended for use as packaging material is essential, particularly when these products come into direct contact with food. It is well known that plastics are not inert and that their residual monomers, starting substances, and additives are able to migrate into the food they contact. Among plastics, styrene is a common compound found in many plastic containers that can also be produced by the oxidation of Penicillium roqueforti used in gorgonzola Protected Denomination of Origin cheese manufacturing. Therefore, solid-phase microextraction combined with gas chromatography/mass spectrometry was applied in the present work to determine the styrene content in packaged and unpackaged gorgonzola cheese samples to understand styrene migration phenomena from plastic containers.

DETERMINATION OF CORTISOL, CORTISONE, PREDNISOLONE AND PREDNISONE IN BOVINE URINE BY LIQUID CHROMATOGRAPHY–ELECTROSPRAY IONISATION SINGLE QUADRUPOLE MASS SPECTROMETRY

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.

Release of ethylbenzene and styrene from plastic cheese containers.

Release of ethylbenzene and styrene from plastic cheese containers L. M. Chiesa & S. Soncin & S. Panseri & C. Cantoni Published online: 12 August 2008 # Springer Science + Business Media B.V. 2008