F. Lorenzo

Optimisation of a two-dimensional on-line coupling for the determination of anisoles in wine using ECD and ICP-MS after SPME-GC separation

“Cork taint”, a musty–mouldy off-odour, represents one of the most serious problems in the wine industry. 2,4,6-Trichloroanisole (TCA), along with other compounds, is known to be responsible for this effect. For this purpose, the present work reports a new method based on headspace solid-phase microextraction (HS-SPME) followed by gas chromatographic (GC) separation and a two-dimensional detection by coupling an electron capture detector (ECD) to an inductively coupled plasma mass spectrometer (ICP-MS) for TCA, 2,6-dichloroanisole (DCA) and 2,4,6-tribromoanisole (TBA) determination. The in-series use of ECD and ICP-MS detectors combine halogen sensitivity from ECD with the selectivity of ICP-MS to confirm these compounds in complex matrices. Different ICP-MS conditions, such as forward power, carrier gas flow and the addition of small percentages of alternate gases have been optimised in the coupling HS-SPME-GC-ECD-ICP-MS. A chemometric approach has been performed for this purpose to obtain the highest sensitivity for all the analytes simultaneously inside the experimental domain. The optimised method shows good detection limits for all the analytes, as well as high precision and sample throughput. Finally, the method has been applied to the analysis of haloanisoles in different red and white Spanish wines. Recovery experiments performed on these matrices proved the method reliability.

Analytical characterization of bioactive metal species in the cellular domain (metallomics) to simplify environmental and biological proteomics

The speciation approach for the characterization of low-mass metal species including sample treatment and storage is at present a well-established topic based on chromatography-atomic detector coupling. More recently, new endogenous and exogenous metal species from biological systems are attracting considerable interest. Bioactive molecules such as proteins, DNA restriction fragments, phytochelatins, metallothioneins and others are target species of a new generation of analytical tools (bioanalysis) which substitute the traditional atomic detectors based on the use of photons (AAS, FPD, ICP-AES, AFS) by mass detectors (MS and ICP-MS) for ion characterization. Several cases related to biological molecules involving proteins and multiprotein systems, in which frequently metals (metallomics) participate, are described, and a generic metallomic analytical approach is proposed for the identification and quantification of metalloproteins, and other metal molecules present in living systems. In this work, a multiplexed analytical approach (MAA) is described on the basis of three experimental components: (1) a separation technique—selectivity component; (2) a highly sensitive elemental detector—sensitivity component; and (3) a molecule-specific detector, generally based on mass spectrometry—structural component. This approach brings together both elemental and molecular detectors to simplify the identification of metal-tagged biomolecules in environmental, food, and health studies.