▎ 摘　　要

A new material, graphene oxide/polypyrrole (GO/Ppy), was synthesized by mixing graphene oxide and polypyrrole in a specific proportion. It possesses a unique structure similar to that of foam. A home-made pipette-tip solid-phase extraction (PT-SPE) device, which is more simple and convenient than traditional devices, was used for saving reagents and operation time. When GO/Ppy was used as the adsorbent of PT-SPE for determining three auxins (indole-3-propionic acid, indole-3-butyric acid, and 1-naphthaleneacetic acid) present in trace amounts in papaya juice, it showed high affinity and adsorption capacity for all the three auxins. GO/Ppy-PT-SPE also had a significant capacity for eliminating the interferences from the papaya juice matrix. Under optimized conditions, a good linearity of auxins was obtained in the range 16.3-812.5 ng g(-1); the average recoveries at the three spiked levels of the three auxins ranged from 89.4% to 105.6% with the relative standard deviations