Fig. 4From: Simultaneous determination of ethyl glucuronide, cocaine, cocaethylene, and benzoylecgonine in hair by using LC–MS/MSComparison of two different types of C18 columns for EtG: a Xselect HSS T3 XP C18 column (2.5 μm, 2.1 × 150 mm particle size) and b Atlantis PREMIER BEH C18 AX column (2.5 μm, 2.1 × 100 mm particle size)Back to article page