A Simple and Rapid Colorimetric Determination for Nitrazepam in Alkaline Solution

Several investigations in our laboratory have shown that nitrazepam turns yellow in alkaline medium and that the color solution in the ultraviolet region has maximum absorption at a wavelength of 366 nm. In the study here, chromatic reactions were studied at 10^0, 10^<-1>, 10^<-2>, 10^<-3> and 10^<-4> N concentrations of sodium hydroxide. The most suitable result was obtained with 10^<-1> sodium hydroxide and the optical density was intensified by heating in a water bath at 100℃ for 30 minutes. The calibration curve was linear at 2 to 16 μg/ml concentration and its regression equation was given by Y=0.069X -0.017 (0.063＜β＜0.075, α=0.05), where Y is absorbance at 370 nm and X is the concentration of nitrazepam (μg/ml). This method of colorimetric determination for nitrazepam is simple, rapid and reproducible. Hence, it is considered applicable for analysis of nitrazepam in forensic chemistry.