Details are in this study:
“Molecularly imprinted coated graphene oxide solid-phase extraction monolithic capillary column for selective extraction and sensitive determination of phloxine B in coffee bean,” Haiyun Zhai, Zihao Su, Zuanguang Chen, Zhenping Liu, Kaisong Yuan, and Lu Huang, Analytica Chimica Acta, vol. 865, no. 20 March 2015, pp. 16–21. The authors are at Guangdong Pharmaceutical University and Sun Yat-sen University, Guangzhou, China.
BONUS: This video is labeled “Coffee Break at Graphine Week“: