Determination of curcumin in turmeric using magnetic iron oxide nanoparticles as solid phase extractor and HPLC

Abstract

Curcumin, a derivative of Curcuma longa L., is used extensively in the food industry and researches have shown the health benefits of this compound [1]. In this work, a novel, simple and rapid method for extraction and determination of curcumin in turmeric was performed using magnetic iron oxide nanopaticles (MIONs) as solid phase extractor and HPLC. The unique properties of nanoscale materials offer excellent prospects for designing new methods and instrumentation for chemical analysis [2]. The MIONs were synthesized according to the method proposed by Laurent et al. [3]. The average size of nanoparticles was in the range of 90nm which was determined by using atomic force microscopy (AFM) (Fig.1). Extraction of curcumin is based on adsorptionof Fe (3+)-curcumin complex on MIONs. Desorption of analyte was performed by NaOH solution containing methanol in order to dissolve the desorbed analyte. Various parameters affecting the extraction recovery such as: pH, volume and concentration of NaOH as desorbing reagent, and concentration of Fe (+3) and percentage of methanol were investigated and optimized. These optimized parameters were: pH=2.0, 1.5 mL of 0.2M NaOH containing 30% methanol and 0.1M of Fe (3+), respectively. The intra-day precision (R.S.D.) was 4.0% and inter-day R.S.D. was less than 7.0%. The preconcentration factor of 100 was achieved in this method. The proposed procedure has been successfully applied to the determination of curcumin in turmeric. Keywords: Curcumin, turmeric, Magnetic iron oxide nanoparticles, Solid phase extraction, Determination, HPLC