A highly selective nanocomposite based on MIP for curcumin trace levels quantification in food samples and human plasma following optimization by central composite design.

A selective and rapid method was developed for quantification of curcumin in human plasma and food samples using molecularly imprinted magnetic multiwalled carbon nanotubes (MMWCNTs) which was characterized with EDX and FESEM. The role of sorbent mass, volume of eluent and sonication time on response in solid phase microextraction procedure were optimized by central composite design (CCD) combined with response surface methodology (RSM) using Statistica. Preliminary experiments reveal that among different solvents, methanol:dimethyl sulfoxide (4:1V/V) led to efficient and quantitative elution of analyte. A reversed-phase high performance liquid chromatographic technique with UV detection (HPLC-UV) was applied for detection of curcumin content. The assay procedure involves chromatographic separation on analytical Nucleosil C18 column (250×4.6mm I.D., 5µm particle size) at ambient temperature with acetonitrile-water adjusted at pH=4.0 (20:80, v/v) as mobile phase at flow rate of 1.0mLmin-1, while UV detector was set at 420nm. Under optimized conditions, the method demonstrated linear calibration curve with good detection limit (0.028ngmL-1) and R2=0.9983. The proposed method was successfully applied to biological fluid and food samples including ginger powder, curry powder, and turmeric powder.