Analytes (urine samples) Calibration equations Correlation coefficient LOQ (ng/mL) LOD (ng/mL) Nitrendipine Nisoldipine Y=5.02×104 x－1.05×102 Y=4.25×104 x+1.46×102 r2 =0.9998 r2 =0.9996 30 30 10 10

Table 1: Calibration curve, LOD and LOQ of nitrendipine, nisoldipine from urine samples.