An amperometric sensor based on hemin adsorbed on silica gel modified with titanium oxide for electrocatalytic reduction and quantification of artemisinin

• Published in: Talanta (Oxford) 2008-12, Vol.77 (2), p.909-914
• Main Authors: Reys, José Rui M., Lima, Phabyanno R., Cioletti, Alessandra G., Ribeiro, Adriana Santos, de Abreu, Fabiane Caxico, Goulart, Marília O.F., Kubota, Lauro T.
• Format: Article
• Language: English
• Subjects: Amperometric sensor; Analytical chemistry; Artemisinin; Chemistry; Electrochemical methods; Exact sciences and technology; General, instrumentation; Hemin; Silica gel; Titanium oxide
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2008.07.043

The present work describes the development of an amperometric sensor based on hemin immobilized on a titanium oxide modified silica toward detection of artemisinin (ARN) in neutral medium at an applied potential of −0.5 V vs. Ag/AgCl. The sensor presented its best performance in 0.1 mol L −1 phosphate buffer solution, at pH 7.0. After optimizing the operational conditions, the sensor provided a linear response range for ARN reduction from 50 nmol L −1 to 1000 nmol L −1 with a sensitivity, detection and quantification limits of 24.66 A L mol −1, 15 nmol L −1 and 52 nmol L −1, respectively. The proposed sensor showed a stable response for at least 80 successive determinations. The repeatability of the measurements with the sensor and the preparation of a series of electrodes, evaluated in terms of relative standard deviation, were 4.1% and 5.0%, respectively, for n = 10. The developed sensor was applied for the determination of ARN in the crude extracts of A. vulgaris L and the average recovery for these samples is 101.4 (± 3.1)%.