Optimization of the spectroscopic method using potassium peroxymonosulfate for determination of antioxidant capacity Marjanović, A. a, * , eđibegović, J. a , Popovac, S. a , Omeragić, E. a , Korać, F. b , Čaklovica, F. c , Turalić, A. a , Šober, M. a a Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, Sarajevo, BiH b Faculty of Scence, Department of Chemistry, University of Sarajevo, Zmaja od Bosne 33-35, Sarajevo, BiH c Faculty of Veterinary Medicine, University of Sarajevo, Zmaja od Bosne 90, Sarajevo, BiH INTRODUCTION Reactive oxygen species (ROS) are byproducts of normal cellular metabolism. Uncontrolled ROS production leads to their accumulation in cells, where they can cause oxidative damage, due to oxidative stress. Endogenic antioxidant repair systems are not enough to prevent disruption of normal cellular homeostasis, which requires substitution with exogenic antioxidants (Kunwar and Priyadarsin, 2011). For epidemiologic purposes it would be useful to determine total antioxidant capacity (TAC) of different classes and types of foods. So far many in vitro and in vivo methods for determination of TAC have been developed. In this study we were testing possible usage of commercial tablets for dental prosthesis, containing potassium peroxymonosulfate as a reagent for determination of antioxidant capacity in vitro. Our aim was to develop fast, simple and cheap method for determination of antioxidant capacity that will be suitable for laboratories with modest resources. In order to test our method, antioxidant capacity of selected samples was determined and compared with the result obtained using classical FRAP method. EXPERIMENTAL For determination of antioxidant capacity of selected food products, effervescent tablets for cleaning dental prosthesis, containing potassium peroxymonosulfate were used. This method was originally proposed by Al- Shahrani, Zaman and Amanullah (2013), but in this study method was modified and improved. In order to test this spectrophotometric method five samples available at the market in Bosnia and Herzegovina were analyzed: the Noni juice (Morinda citrifolia L., Rubiaceae), semi sweet red wine from Herzegovina, dry white wine from Herzegovina, 100% natural tomato juice (Lycopersicum esculentum Mill., Solanaceae) and Goji berries (Lycium barbarum L., Solanaceae). Goji berries (5 g of homogenized sample) were extracted with 25 mL of boiled water. After 10 minutes, sample was filtered, and obtained infusion was used for further analysis. All the other samples were analyzed without prior preparation For each sample 1 mL was mixed with 10 mL of reagent solution. All the spectroscopic measurements (Spectronic Genesis 2 UV/VIS spectrometer) were performed at 616 nm, with reagent solution as blank. Bulletin of the Chemists and Technologists of Bosnia and Herzegovina Print ISSN: 0367-4444 Online ISSN: 2232-7266 2017 49 31-34 UDC: __________________________ Original Scientific Paper Article info Received: 22/11/2017 Accepted: 13/12/2017 Keywords: antioxidants potassium peroxymonosulfate EAPK FRAP *Corresponding author: E-mail: aca1902@gmail.com Phone: 00-387-61-709562 Fax: 00-387-33-586178 Abstract: In this study, we were testing possible usage of commercial tablets for dental prosthesis, containing potassium peroxymonosulfate as a reagent for determination of antioxidant capacity in vitro. Our aim was to develop fast, simple and cheap method for determination of antioxidant capacity that will be suitable for laboratories with modest resources. This method was previously proposed, but we have chosen somewhat different approach. Because of the quite narrow linear range, when ascorbic acid was used as standard, for the preparation of the calibration curve, we have used a catechin in the concentration range from 0.125 mg/mL to 12.5 mg/mL. Obtained calibration curve was linear with correlation coefficient of R 2 =0.992 and it was used for further determination of antioxidant capacity of selected samples. In order to test the possibility of this method for determination of antioxidant capacity of real samples, we have used five samples which antioxidant capacity was proven in previous testing with different in vitro and in vivo methods.