59-05-032 Proceeding

72 Proceedings of the Princess Maha Chakri Sirindhorn Congress 12.43, 15.31, 26.60 and 31.89 minutes, respectively and the resolution values were represented as 2.98, 3.39, 8.68 and 5.88, respectively (Figure 1). 2) LOD and LOQ The LOD and LOQ were calculated from ratio of signal to noise (S/N). The LOD and LOQ of 4 drugs were 0.004 and 0.180 µg/L (lorazepam), 0.082 and 0.210 µg/mL (alprazolam), 0.047 and 0.158 µg/mL (diazepam) and 0.037 and 0.113 µg/mL (midazolam), respectively. 3) Linearity and range The linearity range of lorazepam, alprazolam, diazepam and midazolam was 0.0104- 52.10 µg/mL, 0.0103-10.30 µg/mL, 0.0101-15.10 µg/mL and 0.0412-1.50 µg/mL, respectivelywhich the coefficient of determination were in an acceptable range (r 2 > 0.999) (Table 1). 4) Accuracy and precision Accuracy and precision of the method was quantified by 6 times analyzed of spiked sample of 4 BZDs in the same analytical runs, and acceptable values were 80-120%recovery Figure 1 The chromatograms of matrix blank plasma (A), and spiked plasma sample with internal standard, lorazepam, alprazolam, diazepam and midazolam. (B), using an isocratic solvent, 10mM KH2PO4, pH 5.8: acetronitrile: methanol (58:20:22) (v/v/v) as mobile phase and detection at 210 nm.