2020 Volume 69 Issue 3 Pages 105-113
In this study, the method for separetion and measurement using normal phase LC/MS/MS for levofloxacin and (R)-ofloxacin, which are enantiomers that are difficult to separete by reversed phase LC, was investigated. The mobile phase is t-butyl methyl ether/ethanol/acetic acid/ethylenediamine (30 : 70 : 0.2 : 0.2, v/v/v/v), and the column is phenomenex Lux i-Cellulose-5 (150 × 2.0 mm i.d., 3 μm). The two substances could be separeted under this condition. The calibration curves for both levofloxacin and (R)-ofloxacin showed good linearity in the range of 0.10 to 100 ng mL−1, and the lower limit of instrument detection was levofloxacin: 0.22 ng L−1, (R)-ofloxacin: 0.33 ng L−1. As a result of applying this method to the eluates extracted from a water sample with a polymer-based reversed-phase solid-phase column and ion-exchange reversed-phase mixed solid-phase column, levofloxacin 420 ng L−1 and (R)-ofloxacin 1.7 ng L−1 were detected from sewage treated water, sensitive enantio-separetion. For then, a determination that can be applied to environmental water sample measurements has been made possible.