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The present work studies the effectiveness of the use of triacylglycerols (TAGs) for the quantification of olive oil in blends with vegetable oils. The determinations were obtained using high-performance liquid chromatography (HPLC) coupled to a Charged Aerosol Detector (CAD), in combination with Partial Least Squares (PLS) regression and using interval PLS (iPLS) for variable selection. Results revealed that PLS models can predict olive oil concentrations with reasonable errors. Variable selection through iPLS did not improve predictions significantly, but revealed the chemical information important in the chromatogram to quantify olive oil in vegetable oil blends., (Copyright © 2011 Elsevier B.V. All rights reserved.)

In this paper, a combination of a flow injection analysis (FIA) system with micellar-enhanced photochemically induced fluorescence (MEPIF) detection is presented as a powerful alternative for the rapid and sensitive analysis of chlorophenoxyacid herbicides. These compounds do not show native fluorescence but they can be photolysed into strongly fluorescence photoproducts after direct irradiation with ultraviolet light. The use of a cationic surfactant such as cetyltrimethylammonium chloride (CTAC) provides a considerable enhancement of photochemically induced fluorescence intensity and the nature of the technique allows a possible and easy adaptation to a FIA system. In this sense, parameters related to the nature of the analytical signal (pH, irradiation times, surfactant concentration) and to the FIA manifold (injection volume, flow rate and reactor length) have been optimised. Linear calibration graphs, with three replicates for each concentration value were established in the range of 0.2-5.0 mug ml(-1) for 2,4-Dichlorophenoxyacetic acid (2,4-D) and 0.1-5.0 mug ml(-1) for Mecoprop (MCPP). The IUPAC detection limits were 73.2 and 33.5 ng ml(-1) for 2,4-D and MCPP, respectively. Satisfactory recoveries were obtained in the analysis of these herbicides in spiked waters.