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

• Main Authors: Vieira Iolanda Cruz, Lupetti Karina Omuro, Fatibello-Filho Orlando
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 2003-01-01
• Series: Química Nova
• Subjects: crude extract; carbon paste; paracetamol
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422003000100009

Crude extracts of several vegetables such as peach (Prunus persica), yam (Alocasia macrorhiza), manioc (Manihot utilissima), artichoke (Cynara scolymus L), sweet potato (Ipomoea batatas (L.) Lam.), turnip (Brassica campestre ssp. rapifera), horseradish (Armoracia rusticana) and zucchini (Cucurbita pepo) 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-acetyl-p-benzoquinoneimine which the electrochemical reduction back to paracetamol was obtained at a peak potential of <FONT FACE=Symbol>fraction three-quarters</FONT>0.10V. A cyclic voltammetric study was performed by scanning the potential from + 0.5 to <FONT FACE=Symbol>fraction three-quarters</FONT> 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.