Sensitive determination of psoralen and isopsoralen in Fructus Psoraleae by online solid phase microextraction with a porphyrin-based porous organic polymer modified capillary

A novel porphyrin based porous organic polymer modified capillary (PPOP-capillary) was prepared for the extraction of psoralen and isopsoralen in Fructus Psoraleae. Fructus Psoraleae is an important traditional Chinese medicine in clinical therapy. Sensitive and effective extraction and determination of psoralen and isopsoralen benefit the quality control in Fructus Psoraleae and related preparations. PPOPs were immobilized on the inner wall of the capillary by a bottom-up approach. The formation of PPOPs has been confirmed by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. An online solid phase microextraction coupled with HPLC method was developed for selective extraction and analysis of psoralen and isopsoralen in aqueous solutions. The proposed method showed a good linear range of 0.05–100 ng mL−1 with a low limit of detection of 0.01 ng mL−1. The method was also applied for the extraction of psoralen and isopsoralen in Fructus Psoraleae, which showed high enrichment efficiency and good clean-up capacity. Recoveries were calculated to be 93.3–96.7% with relative standard deviations less than 1.6%.