A novel, simple, sensitive, and selective kinetic spectrophotometric method has been developed for the determination of lorazepam in pharmaceutical and bioloical samples. The procedure is based on the catalytic effect of lorazepam on the Janus Green–bromate reaction system. The change in absorbance was followed spectrophotometrically at 618 nm. To obtain the maximum sensitivity, the reagents concentration, temperature, and time were optimized by one at the time method. Under optimum experimental conditions, the calibration curve was linear over the range 0.3–19.5 μg/mL of lorazepam, including two linear segments. The relative standard deviations (n = 5) for 1.0, 5.0, and 15.0 μmol/L of lorazepam were 1.09, 1.03, and 0.97%, respectively. The limit of detection was 0.08 μg/mL of lorazepam. An experimental check under these optimal conditions confirmed good agreement in the RSM results. The developed method was successfully applied for the determination of lorazepam in real samples, and the obtained results are in a good agreement with those using HPLC.

开发了一种新颖，简单，灵敏和选择性的动力学分光光度法，用于测定药物和生物样品中的劳拉西m。该程序基于劳拉西m对Janus Green-溴酸盐反应体系的催化作用。分光光度法在618nm下跟踪吸光度的变化。为了获得最大的灵敏度，一次通过时间方法对试剂的浓度，温度和时间进行了优化。在最佳实验条件下，在劳拉西m的0.3-19.5μg/ mL范围内，校准曲线是线性的，包括两个线性部分。相对标准偏差（n= 5）劳拉西m的1.0、5.0和15.0μmol/ L分别为1.09、1.03和0.97％。检出限为劳拉西m 0.08μg/ mL。在这些最佳条件下进行的实验检查证实了RSM结果的一致性。所建立的方法成功地用于实际样品中劳拉西the的测定，所获得的结果与使用HPLC的结果吻合良好。