Ultramicro chitosan-assisted in-syringe dispersive micro-solid-phase extraction for flavonols from healthcare tea by...

A novel dispersive micro-solid-phase extraction (DMSPE) method using ultramicro chitosan as an adsorbent was proposed for the analysis of flavonols in Flos Sophorae tea, with detection by ultra-high performance liquid chromatography. Various parameters affecting the extraction recovery, including the concentration and viscosity of chitosan, extraction time and the pH of the sample solution were investigated and optimized. The optimized conditions were found to be 0.4μg/mL of sorbent, pH of 7, an extraction time of 1.0min and 100μL of methanol as the elution solvent. The DMSPE method showed excellent linearity (r(2)>0.99) with pre-concentration factor values ranging from 23 to 77-fold. The limits of detection and quantification were 0.22-0.36ng/mL and 0.72-1.21ng/mL, respectively. This method was successfully applied to the analysis of flavonols in Flos Sophorae tea samples, and their recoveries were in the range of 95.2-102.4%.