Determination of Binary Mixtures by Ratio Spectra Derivative

To establish a quantitative method for determination of binary mixtures. The absorption spectrum of the mixture is obtained and the amplitudes at appropriate wavelengths are divided by the corresponding amplitudes in the absorption spectrum of a standard solution of one of the components, and the first derivative of the ratio spectrum is obtained. The concentration of the other component is then determined from a calibration graph. The method has been applied for resolving the quantitative detemination of diphenhydramine in Baichuanpeng tablets, the dissolvent was water with the detection wavelength at 257 nm. The Linearity of icariin was good ( r - 0.999 7 ) in range of 80.0- 120.0 μg·ml-1 ,The average recovery was 101.2% ,RSD of repeatability was 2. 6%. The method was convenient, rapid, accurate and reliable for determination of binary mixtures.