An Approach to Rapid Determination of Tween-80 for the Quality Control of Traditional Chinese Medicine Injection by Partial Least Squares Regression in Near-Infrared Spectral Modeling

Figure 3

Comparison of the spectrum pretreatment results of Tween-80. Raw NIR spectra of full wavelength (a) and spectra preprocessed using SG smoothing (b) and one-dimensional convolution (c), two-dimensional convolution (d), multiplicative scatter correction (e), standard normal variable transformation (f), normalization method (g), one-order derivative convolution + multiplicative scatter correction (h) and two-dimensional convolution + multiplicative scatter correction (i).

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