Determination of paracetamol in pharmaceutical products using a carbon paste biosensor modified with crude extract of zucchini (Cucurbita pepo)

[摘要] 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 (Armoraciarusticana) and zucchini (Cucurbita pepo) were investigated as thesource of peroxidase (POD: EC 1.11.1.7). Among those, zucchini (Cucurbitapepo) crude extract was found to be the best one. This enzyme in the presenceof hydrogen peroxide catalyses the oxidation of paracetamol to N-acetyl-p-benzoquinoneiminewhich the electrochemical reduction back to paracetamol was obtained at a peakpotential of ¾0.10V. A cyclic voltammetric study was performed by scanningthe potential from + 0.5 to ¾ 0.5 V. The recovery of paracetamol from twosamples ranged from 97.3 to 106% and a rectilinear calibration curve for paracetamolconcentration 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-1and the relative standard deviation was less than 1.1% for a solution containing2.5x10-3 mol L-1 paracetamol and 2.0x10-3 molL-1 hydrogen peroxide (n=12). The results obtained for paracetamolin pharmaceutical products using the proposed biosensor and Pharmacopoeial proceduresare in agreement at the 95% confidence level.

[学科分类] 化学（综合）

[关键词] crude extract;carbon paste;paracetamol.