“…The most popular strategy for hapten design to produce antibodies against extriol was using estriol-6-(O-carboxymethyl) oxime, which retains three functional hydroxyl groups of estriol (Freeman & Johnso,1999;Otsuki et al, 1979;Wang, Du, Lin, & Zhuang, 2006). However, in this work, we used the similar strategy for hapten design, but the obtained antibody seemed to be unsatisfactory (Table S1).…”