Solvent and temperature effects of accelerated solvent extraction (ASE) with Ultra-high pressure liquid chromatography (UHPLC-PDA) technique for determination of Piperine and its ICP-MS analysis

Black pepper (Piper nigrum), known as king of spices is the most widely used spice in the world. Though a number of marketed food grade products are available for black pepper, however, the labels does not mention the quality of active drug Piperine (PPN) and level of toxic elements. The study aims to develop a rapid, effective and reliable method for extraction of PPN and a short and sensitive method for quantification of PPN in commercial food samples from different geographical locations i.e. Pakistan, Vietnam and India. For extraction of PPN, Accelerated solvent extraction (ASE) method was utilized whereas, UHPLC-DAD was utilized to quantify the PPN concentration in the extracts. For elemental analysis, ICP-MS was used. Method development and validation revealed optimum temperature (70 degrees C) and solvent (DCM) with extraction yield of 93.89%. The method was applied in commercial samples whereby an extraction yield and %recovery, within a short time of 43 +/- 2 min and least solvent usage of 50.5 +/- 2 ml, was observed for Vietnam (14.83 g; 74.15%) > Pakistan (12.71 g; 63.55%) > India (11.08 g; 55.4%). A calibration curve was constructed for PPN (300-5000 ng/ml) using UHPLC-DAD. A retention time of 3.31 +/- 1 min at 343 nm was noted with a shorter run time of 5 min using a simple mobile phase. The highest concentration of PPN (ng/ml) was observed as; Pakistan, S8 (1,362,614.09) > Vietnam, V8 (1,051,848.04) > India, I8 (768,512.81). For elements, the order was observed as; Vietnam > Pakistan > India, whereas individual order for macro-, micronutrients and trace elements was observed as; K > Ca > Mg > Mn, Fe > Cr > Ni > Ti > Cu > Se > Mo > Co and Sr > Ba > Pb > Pt > Sb > Y. A high extract yield was observed with the use of ASE, as compared to traditional extraction methods, whereas combination of ASE-UHPLC-DAD produced fast and sensitive method for PPN quantification in commercial food samples as a marker for determination of adulteration.