Modified microelectrodes and multivariate calibration for flow injection amperometric simultaneous determination of ascorbic acid, dopamine, epinephrine and dipyrone

Abstract

Flow injection amperometric quantification of ascorbic acid (AA), dopamine (DA), epinephrine (EP) and dipyrone (DI) in mixtures (in the microgram g-1 range) was successfully performed by using an array of microelectrodes with units modified by the electrodeposition of different noble metals, together with multivariate calibration analysis. The four groups of microelectrodes utilized included a pure gold electrode and electrodes modified by electrodeposition of platinum, palladium or a mixture of platinum + palladium. The array of microelectrodes was inserted in a flow cell and the amperometric data acquisition was performed with a four-channel potentiostat. The analysis of the resulting signals was carried out by a multivariate calibration method, using a group of 16 standard mixtures selected by a two-level factorial design. The analysis of synthetic samples and pharmaceutical compounds containing AA and DI led to very similar values to those obtained by the classical iodimetric analysis. The average absolute errors (in microgram g-1) calculated for each analyte were 0.3, 0.2, 0.4 and 0.4 for AA, DA, EP and DI, respectively.

Voltammetric determination of dipyrone using a N,N'-ethylenebis(salicylideneaminato)oxovanadium(IV) modified carbon-paste electrode

“…This flow injection procedure presented a linear response in the dipyrone concentration range from 3.0 x 10 -6 to 3.0 x 10 -5 mol L -1 in an ammonia buffer solution (pH 9.0) at a potential of 0.4 V vs. Ag/AgCl. The flow injection amperometric simultaneous determination of dipyrone, ascorbic acid, dopamine and epinephrine using modified microelectrodes, together with multivariate calibration analysis was proposed by Matos et al 10 It was based on a multi-channel detection system, coupled to a flow cell containing an array of modified microelectrodes. Recently, the same research group developed a flow cell containing a gold electrode from recordable compact discs for the determination of dipyrone in pharmaceutical formulations.…”

Simultaneous voltammetric determination of dopamine and ascorbic acid using multivariate calibration methodology performed on a carbon paste electrode modified by a mer-[RuCl3(dppb)(4-pic)] complex

“…22 In many of these cases, the use of multivariate calibration methods is an alternative to reduce the interferent effect, improving the selectivity of these instrumental methods. [23][24][25][26] This method can be useful for simultaneous determination of dopamine and ascorbic acid when only the modification of the electrode surface is not sufficient to separate significantly the oxidation peaks of both substrates. To our knowledge multivariate calibration methodology has not been combined with voltammetry for the separation of dopamine and ascorbic acid.…”

Simultaneous voltammetric determination of dypirone and paracetamol with carbon paste electrode and multivariate calibration methodology

“…The same research group developed a flow cell containing a gold electrode from recordable compact discs for the determination of dypirone in pharmaceutical formulations. 39 This paper reports the simultaneous electrochemical determination of dypirone (DIP) and paracetamol (PAR) by differential pulse voltammetry technique (DPV) using an unmodified carbon paste electrode. Because the voltammetric peaks of DIP and PAR overlaps, the multivariate calibration methodology based on Partial Least Square Regression (PLSR) was proposed.…”

“…However, different from paracetamol, the electrochemical reaction and its determination using electroanalytical techniques has been less investigated. [39][40][41] Matos et al 39 proposed a flow injection analysis based on a multi-channel detection system for simultaneous amperometric determination of dypirone, ascorbic acid, dopamine and epinephrine using an array of modified microelectrodes, together with multivariate calibration analysis. The same research group developed a flow cell containing a gold electrode from recordable compact discs for the determination of dypirone in pharmaceutical formulations.…”

“…The three most commonly used multivariate calibration methods are multiple linear regression (MLR), principal component regression (PCR), and partial leastsquares regression (PLSR). [13][14][15] These methods constitute a powerful statistical tool for factor analysis and have been mostly applied to the simultaneous multicomponent analysis of mixtures by spectroscopy, chromatography, and voltammetric methods. [16][17][18][19][20] Paracetamol or acetaminophen ( Figure 1A) is a popular analgesic and antipyretic agent.…”