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

Abstract

Esse artigo descreve a determinação simultânea de dipirona (DIP) e de paracetamol (PAR) utilizando a técnica de Voltametria de Pulso Diferencial (VPD) e eletrodo de pasta de carbono não modificado. Devido à sobreposição dos picos voltamétricos de DIP e PAR, a metodologia de calibração multivariada baseada na Regressão de Mínimos Quadrados Parciais (PLSR) foi proposta. O conjunto de voltamogramas obtidos na presença de ambos os analitos em diferentes concentrações foi pré-processado pelos dados centrados na média. Para escolha do número de componentes principais, um procedimento de validação cruzada foi empregado, sendo que quatro componentes principais foram necessárias para obtenção dos menores valores de PRESS (Prediction Residual Error Sum of Squares). Esse modelo explicou aproximadamente 95,5% da variância do conjunto de dados. Os dados obtidos utilizando-se esse modelo mostraram uma alta correlação entre as concentrações reais e previstas. Entretanto, para baixas concentrações do PAR, os erros relativos aumentaram para 25%. Comparando-se os valores de RMSEP (Root Mean Square of Error Prediction), entre PAR e DIP, foi observado que este foi menor para DIP, provavelmente devido a maior quantidade de informação analítica apresentada pelos voltamogramas desse analito quando comparado ao processo redox de PAR, o qual devido a sua oxidação irreversível apresenta apenas um único pico. This paper shows the simultaneous electrochemical determination of dypirone (DIP) and paracetamol (PAR) by differential pulse voltammetry technique (DPV) using an unmodified carbon paste electrode. Because of the overlapping of the voltammetric peaks of DIP and PAR, the multivariate calibration methodology based on Partial Least Square Regression (PLSR) was proposed. The data pre-treatment used in this process was mean centering and to choose the principal component number a cross validation procedure was used (leave-one-out). Four principal components were necessary to obtain the lowest PRESS (Prediction Residual Error Sum of Squares). The statistics showed that this model explains approximately 95.5% of the variance from the data set. Using this model, high correlation between real and predicted concentrations was observed. However, for low concentrations of PAR the relative error increased to 25%. Comparing RMSEP (Root Mean Square of Error Prediction) between PAR and DIP, it was observed that it was lower for DIP probably due to higher analytical information in the voltammograms for this analyte when compared to the electrochemical process of PAR, which presented only one potential peak due to its irreversible oxidation.

Enhanced voltammetric detection of paracetamol by using carbon nanotube modified electrode as an electrochemical sensor

“…Among several painkillers, paracetamol (PC) has commonly been used for fever of viral and bacterial sources and pain relief [3]. PC (acetaminophen, N-acetyl-p-aminophenol) diminishes mild-moderate pain related with headache, migraine, toothache, backache, muscular aches, and postoperative pains [4][5][6]. It is the best substitute for patients who are sensitive to aspirin, which is also used as an analgesic [7][8].…”

Salicylic Acid Boosts the TiO2 and ZnO-Mediated Photodegradation of Paracetamol

“…Considering that the anodic peak potential of salicylic acid (Epa = 0.94 V) 22 is higher than the paracetamol (Epa = 0.77 V) 23 , it should be expected, the last one as more susceptible, or at least, similar to salicylic acid when submitted to photodegradation. In fact, as well-established, the oxidability increase as the Epa value decreases 23 . However, an unexpected behavior was observed when these compounds were submitted to TiO 2 -mediated photodegradation.…”

“…This conclusion is also consistent with the lower Epa value (0.77 V) of paracetamol compared to salicylic acid (0.93 V). Indeed, the oxidizability of phenolic compounds increases as their anodic peak potential decreases 22,23,28 . To evaluate this chemical feature, the reactivity of the studied compounds was tested regarding their efficacy as reducing agents in the DPPH scavenging assay.…”

Analytical chemistry in Brazil: healthy and growing

“…193 Simultaneous voltammetric determination of dypirone and paracetamol with a carbon paste electrode was also feasible by means of multivariate calibration based on PLS. 194 In other approach, the cationic surfactant cetylpyridinium bromide was used to separate the oxidation peaks of ascorbic and uric acids by 282 mV, aiming simultaneous determination of the analytes in urine samples by differential pulse voltammetry. 195 Boron-doped diamond electrodes show properties notably different from those presented by electrodes of conventional materials, such as stability in aggressive alkaline and acidic media, low and stable background current and working potential range larger than 3.5 V. Electrodes of this material were applied for the simultaneous voltammetric determination of aspartame and cyclamate 196 and paracetamol and caffeine, 197 in view of the separation of the oxidation peak potential of 400 and 550 mV, respectively.…”