Abstract: Objective: To establish a simple and nondestructive evaluation method of CⅡ-3 extract from Periplaneta americana
based on infrared spectrum and chemometrics. Methods: Infrared spectra of 10 batches of CⅡ-3 samples were established by infrared
spectroscopy, and the spectra were optimized by baseline correction, ordinate normalization and 15-point smoothing. Origin 9.1
software was used to characterize and analyze the spectral data, and the fingerprints of 10 batches of CⅡ-3 samples were established,
and similarity analysis and principal component analysis were performed. Results: The main characteristic peaks of the functional
group region in infrared spectra of 10 batches of CⅡ-3 samples were 3 300, 2 960, 2 930, 1 660, 1 630, 1 550, 1 450, 1 390 cm-1. The
main characteristic peaks in fingerprint region were 1 240, 1 080, 621, 546 cm-1. The peak shape, position and intensity of infrared
spectra were similar among different batches, and the correlation coefficients were all above 0.960. The results of principal component
analysis showed that 10 batches of samples were clustered into one category. Conclusion: The method has the advantages of simple
operations, strong specificity, no damage to the sample, and can be used for the quality evaluation for CⅡ-3 samples.

Key words: Periplaneta americana, CⅡ-3, infrared spectroscopy, similarity analysis, principal component analysis, nondestructive
quality evaluation