Fast and reliable analytical methodologies are required for quality control of plants in order to assure human health. Ultrasound-assisted extraction in combination with total reflection X-ray fluorescence is proposed as a fast and simple method for multielemental analysis of plants on a routine basis. For this purpose, five certified reference materials have been analysed for the determination of P, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn and Pb.
View Article and Find Full Text PDFIn this work, a new method based on the combination of dispersive liquid-liquid microextraction (DLLME) with microvolume spectrophotometry has been developed as a greener and miniaturized alternative to the 5530 APHA standard method for determining phenols in water and wastewater. The method relies on the oxidative coupling of phenols with 4-aminoantipyrine (4-AAP). In order to preconcentrate the dye formed, the classical liquid-liquid extraction used in the 5530 APHA method (involving 500 mL of sample and 50 mL of trichloromethane) has been replaced by DLLME (with 5 mL of sample, 50 μL of trichloromethane and 200 μL of acetonitrile).
View Article and Find Full Text PDFA simplified and miniaturized procedure for the determination of Cd and Cu bound to metallothioneins (MTs) by ICP-MS in mussel tissue has been developed. Cytosol preparation was based on the indirect sonication of slurries containing the lyophilized sample dispersed in 1 mL of extractant by means of a sonoreactor Cup-Horn. Rabbit liver MTs (Apo-MT-I, Apo-MT-II and Cd(7)-MT-II) and a conventional cytosol preparation procedure were used for validation purposes.
View Article and Find Full Text PDFWater was sampled monthly from September 2005 to August 2006 at 14 stations distributed throughout the coastal system of Anllóns-Laxe, from where 30 surface sediment samples were also taken. After filtration through 0.22 μm polycarbonate filters, dissolved inorganic and total arsenic (UV oxidation) concentration was determined by HG-AFS.
View Article and Find Full Text PDFA miniaturized methodology for the determination of phosphate in waters has been developed by combining directly suspended droplet microextraction (DSDME) with microvolume spectrophotometry. The method is based on the extraction of the ion pair formed between 12-molybdophosphate and malachite green onto a microdrop of methyl isobutyl ketone and subsequent spectrophotometric determination with no dilution. An enrichment factor of 325 was obtained after 7.
View Article and Find Full Text PDFTumorous and adjacent non-tumorous paired biopsies from 38 patients with colorectal cancer were analyzed by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry after low-volume microwave digestion. 18 elements were investigated: Ag, Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, P, Pb, S, Se and Zn. Different chemometric tools were used for data evaluation: Wilcoxon signed rank test, Hieratical clustering analysis, principal component analysis (PCA) and linear discriminant analysis (LDA).
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