2.5. Validation Procedure

The proposed method was validated according to guidelines established in the United States [21] and Taiwan [22] on the basis of evaluations of linearity, the ME, the limit of detection (LOD), the limit of quantification (LOQ), precision, and accuracy. We described these detailed QA/QC procedures in a previous study [19]. In addition, the retention time, MS parameters (e.g., ion transitions for quantification and confirmation), and collision energy of BPs obtained in the MRM mode and the chromatographic conditions were optimized [20].