CE has shown to have a big potential for chiral separations, with advantages such as high efficiency, high resolution, and low sample and reagents consumption. Nevertheless, when UV detection is employed, CE has some drawbacks, especially the low sensitivity obtained due to the short optical path length. Notwithstanding, sensitivity improvements can be achieved when different approaches are employed, such as sample treatment strategies (off-line or on-line), in-capillary sample preconcentration techniques, and/or alternative detection systems to UV-Vis (such as fluorescence, conductimetry, electrochemiluminiscence, MS, etc.). This article reviews the most recent methodological and instrumental advances reported from June 2011 to May 2013 for enhancing the sensitivity in chiral analysis by CE. The sensitivity achieved for the enantioseparated analytes and the applications carried out using the developed methodologies are also summarized.

An untargeted metabolomic approach using liquid chromatography coupled to electrospray ionization time-of-flight mass spectrometry was developed in this work to identify novel markers for saffron authenticity which is an important matter related to consumer protection, quality assurance, active properties, and also economical impact (saffron is the most expensive spice). Metabolic fingerprinting of authentic and suspicious saffron samples from different geographical origin was obtained and analyzed. Different extracting protocols and chromatographic methodologies were evaluated to obtain the most adequate extracting and separation conditions. Using an ethanol/water mixture at pH 9.0 and an elution gradient with a fused core C18 column enabled obtaining the highest number of significant components between authentic and adulterated saffron. By using multivariate statistical analysis, predictive classification models for authenticity and geographical origin were obtained. Moreover, 84 and 29 significant metabolites were detected as candidates for markers of authenticity and geographical origin, respectively, from which only 34 metabolites were tentatively identified as authenticity markers of saffron, but none related to its geographical origin. Six characteristic compounds of saffron (kaempferol 3-O-glucoside, kaempferol 3-O-sophoroside, kaempferol 3,7-O-diglucoside, kaempferol 3,7,4'-O-triglucoside, kaempferol 3-O-sophoroside-7-O-glucoside, and geranyl-O-glucoside) were confirmed by comparing experimental MS/MS fragmentation patterns with those provided in scientific literature being proposed as novel markers of authenticity. Graphical Abstract Metabolomic fingerprinting of saffron.

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