A novel reactive paper spray ionization mass spectrometry (RPSI-MS) method was developed for rapid and sensitive detection of estrogens in cosmetics. The method utilizes online derivatization with 2-fluoro-1-methyl-pyridinium-p-toluene-sulfonate (FluMP) to enhance the sensitivity of detection. The method showed good linearity (R² > 0.99), recovery (80–111%), and a low limit of detection (0.001 µg/mL) for estradiol, estriol, and ethinylestradiol. Compared to conventional PSI-MS, RPSI-MS showed a significant sensitivity improvement (34,000–80,000 times). The method is sensitive, eco-friendly, and suitable for rapid testing of estrogens in cosmetics.

D Song, J Liu, Y Liu, K Zacharis