Near Infrared Correlation Coefficient Method with Characteristic Spectral Band for the Determination of Illegal Addition of Sildenafil Citrate in Capsules of Chinese Traditional Medicine / 分析化学

ABSTRACT

A near infrared (NIR) method for the detection of illegal addition of sildenafil citrate in capsules of Chinese traditional medicine was constructed. The diffuse reflectance near infrared spectra were recorded using integrated sphere and fiber optics respectively. Using the spectra of the sildenafil citrate standard as Reference spectra, the threshold of the correlation coefficient was set up based on the minimum effective concentration of the sildenafil citrate. By comparing the threshold with the correlation coefficient between the tested spectra and the Reference spectra in the selected spectral range, the tested sample contains sildenafil citrate is determined. For the integrated sphere method, the spectral range of 6070-5800 cm~(-1) and 4170-4070 cm~(-1) were selected, and 70% was set as threshold. For the fiber method, 6070-5800 cm~(-1) and 65% were used. 79 and 247 batches of the Chinese traditional medicines contained sildenafil citrate collected from the Chinese market were used to validate the two methods separately. The accuracy of the integrated sphere method was 91.14%, and that of f iber method was 87.45%.