Search results for "Thymol blue"
showing 3 items of 3 documents
Determination of titratable acidity and ascorbic acid in fruit juices in continuous-flow systems
1993
Two continuous-flow systems for the determination of titratable acidity and ascrobic acid in fruit juice samples are described. The assemblies permit on-line dialysis of analytes prior to the reaction step, thus improving selectivity and performing sample dilution. Flow systems are built with a channel carrying the donor phase (sample in both determinations) and another channel carrying an acceptor phase, both of them entering the dialyser. The outcoming stream transporting the dialysed sample fills the valve loop, permitting its injection into a carrier stream which continuously passes through the spectrophotometric detector. For the titratable acidity, acceptor phase and carrier are disti…
V2O5 nanowires with an intrinsic iodination activity leading to the formation of self-assembled melanin-like biopolymers
2011
V2O5 nanowires act as biomimetic catalysts resembling vanadium haloperoxidases (V-HPO). The nanowires display iodinating activity as confirmed by a colorimetric assay using thymol blue (TB), UV/Vis spectrophotometry and mass spectrometry (FD-MS). In the presence of dopamine these nanowires catalyze the fast and efficient synthesis of melanin-like biopolymers under mild conditions (aqueous solution, neutral pH and room temperature). The resulting melanin-like biopolymer obtained by the V2O5 nanowire catalysts was characterized by scanning electron microscopy (SEM), X-ray diffraction, UV-Vis, FT-IR and electric conductivity resembling the natural biopolymer both in its chemical and morphologi…
Detection and correction of interferences in spectroscopy techniques
2001
By combining the apparent content curves method and the Youden method, we have developed a strategy for detecting constant and proportional errors in spectroscopy techniques. A method for elimination of spectral interferences (different of blank) is also proposed. To apply of this method there must be a matrix effect that varies with the amount of sample or a simulated matrix effect provided working under different experimental conditions that induce a variation of the analytical signal of the analyte. The proposed procedures have been applied to the determination of methyl orange in presence of phenol red, bromothymol blue and bromocresol purple.