Recent trends in capillary electrophoresis for complex samples analysis: A review.

CE has been a continuously evolving analytical methodology since its first introduction in the 1980s of the last century. The development of new CE separation procedures, the coupling of these systems to more sensitive and versatile detection systems, and the advances in miniaturization technology have allowed the application of CE to the resolution of new and complex analytical problems, overcoming the traditional disadvantages associated with this method. In the present work, different recent trends in CE and their application to the determination of high complexity samples (as biological fluids, individual cells, etc.) will be reviewed: capillary modification by different types of coatings, microfluidic CE, and online microextraction CE. The main advantages and disadvantages of the different proposed approaches will be discussed with examples of most recent applications.

Recent advances in sample pre-treatment for emerging methods in proteomic analysis.

The objective of proteomics is the study of proteins (including their structure elucidation, the characterization of their role in biochemical process, the detection and identification of anomalous modifications in their structures and behavior, etc.) from both a qualitative and quantitative point of view. These studies have to face several difficulties as (a) the intrinsic complexity of protein molecules, (b) the low concentrations of the studied proteins, (c) the complexity of the biological samples (which could lead to interferences from the components of these matrixes), etc. Thus, the sample preparation procedure has a critical importance in order to obtain good separations and sensitivity in the results. In this paper, recent sample treatment methodologies for proteomic studies are reviewed and discussed. These methods include recent innovations in nanoparticle enrichment pre-treatment (for both the selective pre-concentration of the studied protein and the microwave-assisted digestion of the sample), treatments for tissue imaging (based on surface analysis of the studied biological tissues) and protein microarrays analysis (which allows the simultaneous determination of a high number of different proteins or associated species on a glass slide support).

Characterization and authentication of Spanish PDO wine vinegars using multidimensional fluorescence and chemometrics.

This work assesses the potential of multidimensional fluorescence spectroscopy combined with chemometrics for characterization and authentication of Spanish Protected Designation of Origin (PDO) wine vinegars. Seventy-nine vinegars of different categories (aged and sweet) belonging to the Spanish PDOs "Vinagre de Jerez", "Vinagre de Montilla-Moriles" and "Vinagre de Condado de Huelva", were analyzed by excitation-emission fluorescence spectroscopy. A visual assessment of fluorescence landscapes pointed out different trends with vinegar categories. PARAllel FACtor analysis (PARAFAC) extracted the potential fluorophores and their values in the PDO vinegars. This information, coupled with different classification methods (Partial Least Square Discrimination Analysis "PLS-DA" and Support Vectors Machines "SVM"), was able to discriminate the wine vinegar category within each PDO, for which SVM models obtained better results (>92% of classification). In each category, SVM also allows the differentiation between PDOs. The proposed methodology could be used as an analysis method for the authentication of Spanish PDO wine vinegars.

Fluorescence excitation-emission matrix spectroscopy as a tool for determining quality of sparkling wines.

Browning in sparkling wines was assessed by the use of excitation-emission fluorescence spectroscopy combined with PARAllel FACtor analysis (PARAFAC). Four different cava sparkling wines were monitored during an accelerated browning process and subsequently storage. Fluorescence changes observed during the accelerated browning process were monitored and compared with other conventional parameters: absorbance at 420nm (A420) and the content of 5-hydroxymethyl-2-furfural (5-HMF). A high similarity of the spectral profiles for all sparkling wines analyzed was observed, being explained by a four component PARAFAC model. A high correlation between the third PARAFAC factor (465/530nm) and the commonly used non-enzymatic browning indicators was observed. The fourth PARAFAC factor (280/380nm) gives us also information about the browning process following a first order kinetic reaction. Hence, excitation-emission fluorescence spectroscopy, together with PARAFAC, provides a faster alternative for browning monitoring to conventional methods, as well as useful key indicators for quality control.