Citlivá voltametrické metoda pro stanovení antioxidantu pyrogalolu s využitím borem dopované diamantové elektrody

A sensitive voltammetric method for the determination of pyrogallol (PY) was developed employing a boron-doped diamond electrode (BDDE). The composition of the supporting electrolyte was investigated during the development of the methodology. Linear sweep voltammetry (LSV) under the optimized experimental conditions was applied for PY determination with a limit of detection and limit of quantification of 0.85 and 2.82 lmol L-1, respectively. These values are satisfactory for application to real samples. The usability of this method for the quantification of pyrogallol was in range from 2.82 to 296.00 lmol L-1. Finally, the developed method was successfully used for the analysis of real samples of bio diesel produced from rapeseed oil and its blend with diesel fuel. Samples of biodiesel and biodiesel blends were analyzed directly in an electrochemical cell, while samples with very low concentrations of PY in biodiesel were extracted with water using the proposed simple and fast process.Byla vyvinuta voltametrická metoda pro stanovení antioxidantu pyrogalolu s vyžitím borem dopované diamantové elektrody. Tato metoda byla aplikována při stanovení antioxidantu v bionaftě

Citlivá voltametrická metoda stanovení herbicidu metribuzinu s využitím stříbrné pevné amalgámové elektrody

New sensitive voltammetric method for determination of triazinone herbicide metribuzin (MTZ) was developed employing polished and mercury meniscus-modified silver solid amalgam electrode (p-, m-AgSAE). MTZ yielded two reduction signals on both used working electrodes in acidic and slightly acidic media and the positively situated peak [at about -650 mV vs. Ag|AgCl|KCl (sat.)] was found suitable for further analytical measurements. The highest responses were recorded in Britton-Robinson buffer of pH 2 (p-AgSAE) or 3 (m-AgSAE). Various voltammetric techniques like cyclic, linear sweep, and differential pulse voltammetry were used for examination of the voltammetric behavior of MTZ. Parameters of differential pulse voltammetry were optimized and low detection limits were reached (LODm-AgSAE = 6.0 x 10(-8) mol dm(-3) and LODp-AgSAE = 7.5 x 10(-8) mol dm(-3)). Moreover, excellent repeatability of determination and measurements as well was confirmed by low values of relative standard deviations of five repeated determinations [RSD (5) a parts per thousand currency sign 6.0 %] and of 11 repeated measurements [RSD (11) a parts per thousand currency sign 4.5 %], respectively. Finally, practical applicability of newly proposed methods was verified by the analysis of spiked tap and river water and by determination of MTZ in pesticide preparation with excellent results. All the obtained results were compared with those gained for classic mercury electrode.Bylo studováno voltametrické chování herbicidu metribuzinu s využitím stříbrné pevné amalgámové elektrody a byla vyvinuta metoda stanovení této látky. Ta byla splikována při analýze přírodních vod a pesticidního přípravku