Determinação de paracetamol em produtos farmacêuticos usando um biossensor de pasta de carbono modificado com extrato bruto de abobrinha (Cucurbita pepo)

Abstract

were investigated as the source of peroxidase (POD: EC 1.11.1.7). Among those, zucchini (Cucurbita pepo) crude extract was found to be the best one. This enzyme in the presence of hydrogen peroxide catalyses the oxidation of paracetamol to N-acetylp-benzoquinoneimine which the electrochemical reduction back to paracetamol was obtained at a peak potential of -0.10V. A cyclic voltammetric study was performed by scanning the potential from + 0.5 to -0.5 V. The recovery of paracetamol from two samples ranged from 97.3 to 106% and a rectilinear calibration curve for paracetamol concentration from 1.2x10 -4 to 2.5x10 -3 mol L -1 (r=0.9965) were obtained. The detection limit was 6.9x10 -5 mol L -1 and the relative standard deviation was less than 1.1% for a solution containing 2.5x10 -3 mol L -1 paracetamol and 2.0x10 -3 mol L -1 hydrogen peroxide (n=12). The results obtained for paracetamol in pharmaceutical products using the proposed biosensor and Pharmacopoeial procedures are in agreement at the 95% confidence level.

Electrochemical sensors: a powerful tool in analytical chemistry

“…Mattos et al 109 have also developed glucose biosensors using the enzyme glucose oxidase immobilized on Prussian blue films electrodeposited on glassy carbon electrodes. The analytical use of vegetable tissue or crude extracts as enzymatic sources has been extensively studied by Fatibello and co-workers [121][122][123][124][125] and by Angnes and coworkers. 126 Examples of many biosensors and/or flow injection procedures for analysis of compounds of biological, environmental, food, pharmaceutical and industrial interest habe been described using vegetable tissues or crude extracts from sweet potato, 122 avocado, 123 zucchini, peach, yam, cassava, artichoke, turnip, horseradish, 124,125 and tissues from fruits of the palm tree latania sp.…”

Simultaneous Determination of Different Phenolic Compounds Using Electrochemical Biosensor and Multivariate Calibration

“…The obtained paste was then homogenized in a mortar with pestle for 10 min. Although other authors 31,32 have used a longer homogenizing time (20 min), in this work, the homogenization for 10 min was carried out successfully. Finally, the paste was inserted into a glass tube in a manner to allow it to make contact with a nickel/copper wire, in order to be used as working electrodes.…”

“…Polyclar Super R was added (2.5 g) as a protecting agent. 31 Immediately, the extract was filtered using 4 layers of gauze and the filtrate was centrifuged at 1800 rpm for 20 min at 4 °C. The supernatant was collected and divided in several aliquots that were stored in the fridge at 4 °C to be used as the source of tyrosinase.…”

Flow injection analysis of paracetamol using a biomimetic sensor as a sensitive and selective amperometric detector

“…32,33 Electrochemical methods [34][35][36] are an attractive alternative, since they are fast, inexpensive, and can be adapted for portable, disposable and miniaturized applications.…”

“…However, use of modified electrodes, such as biosensors 32,37 and more recently biomimetic sensors, 38 can enable operation at potentials much lower than those normally used, thus decreasing the interference.…”