Fig. 5From: Simultaneous determination of ethyl glucuronide, cocaine, cocaethylene, and benzoylecgonine in hair by using LC–MS/MSRelative S/N ratio of EtG for four types of mobile phases. Mobile phase (A) was 0.1% acetic acid (0.1% AA), 0.1% fomic acid (0.1% FA), and 0.5% formic acid (0.5% FA) in H2O. Mobile phase (B) was acetonitrile (ACN) and methanol (MeOH)Back to article page