A GREEN CHEMISTRY APPROACH TO SYNTHESIS OF Ce(IV) NANOPARTICLES USING ORIGANUM SYRIACUM

INTRODUCTION Cerium(IV) nanoparticles were synthesized using a green synthesis approach with co-precipitation method which relies on the oxidation of Ce(III) to Ce(IV) in basic medium. Green synthesis was carried out with a... [ view full abstract ]

INTRODUCTION
Cerium(IV) nanoparticles were synthesized using a green synthesis approach with co-precipitation method which relies on the oxidation of Ce(III) to Ce(IV) in basic medium. Green synthesis was carried out with a Middle Eastern herb called zahter (origanum syriacum), commonly found in Antakya region of Turkey, due to its high antioxidant and flavonoid capacity.
METHODS
Zahter extract was prepared at 60°C in 100 mL of deionized water in 1:1 dilution. 15 grams of Ce(III) nitrate was added to the extract at 60°C and the mixture was heated to 80°C with constant stirring. At 80°C, 1M Na2CO3 solution was added dropwise until a pH value of 9 was achieved. Then, the mixture was heated for 4-6 more hours at constant temperature. Synthesized particles were ultrasonicated for 30 minutes and washed using acetone/H2O mixture three times. SEM image of the synthesized particles was taken using FEI Quanta FEG 250 Scanning electron microscope.
RESULTS
Analysis of Zahter extract in terms of total antioxidant, phenolic and flavonoid content was performed using CERAC, Classical and modified phenolic content methods and Total flavonoid content method using AlCl3 [1-2] . All measurements were made using a Varian Cary 100 UV-Vis spectrophotometer. Results obtained from total Phenolic content and CERAC methods are represented as Gallic acid equivalents wheras the results obtained from total Flavonoid method are represented as Catechine equivalents.
DISCUSSION
To the best of our knowledge, origanum syriacum was used for the green synthesis of Ce(IV) nanoparticles for the first time. It is clear that due to its high antioxidant capacity, Zahter is capable of reducing Ce(IV) to Ce(III). Results represented in Table 1 show that CERAC is the most convenient and precise method for measuring total antioxidant capacity.
REFERENCES
1. Singleton,V. L., Orthofer,R., Lamuela-Raventos,R.M. (1999). Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent. Methods Enzymol. 299, 152−178.
2. Berker,K.I., Ozdemir,F.A., Ozyurt,D., Demirata,B., & Apak,R. (2013). Modified Folin–Ciocalteu Antioxidant Capacity Assay for Measuring Lipophilic Antioxidants. J. Agric. Food Chem, 61(20), 4783-4791.

Acknowledgments
This research was supported by TUBITAK under project number TBAG 115Z887 and ITU-BAP research project number 39333.