| Description |
Collected sample tissues were weighed and stored at -80℃ until analysis. The frozen tissues were homogenized in five volumes of 80% aqueous methanol containing 0.1% acetic acid, 0.5 mg/L of lidocaine, and d-camphor sulfonic acid (Tokyo Kasei) using a mixer mill (MM 300, Retsch) with a zirconia bead for 6 min at 20 Hz. Following centrifugation at 15,000g for 10 min and filtration (Ultrafree-MC filter, 0.2 mm, Millipore), the sample extracts were applied to an HLB mElution plate (Waters) equilibrated with 80% aqueous methanol containing 0.1% acetic acid. |