AO–MW–PLS method applied to rapid quantification of teicoplanin with near-infrared spectroscopy

Abstract

Teicoplanin (TCP) is an important lipoglycopeptide antibiotic produced by fermenting Actinoplanes teichomyceticus. The change in TCP concentration is important to measure in the fermentation process. In this study, a reagent-free and rapid quanti¯cation method for TCP in the TCP-Tris-HCl mixture samples was developed using near-infrared (NIR) spectroscopy by focusing our attention on the fermentation process for TCP. The absorbance optimization (AO) partial least squares (PLS) was proposed and integrated with the moving window (MW) PLS, which is called AO-MW-PLS method, to select appropriate wavebands. A model set that includes various wavebands that were equivalent to the optimal AO-MW-PLS waveband was proposed based on statistical considerations. The public region of all equivalent wavebands was just one of the equivalent wavebands. The obtained public regions were 1540-1868 nm for TCP and 1114-1310 nm for Tris. The root-mean-square error and correlation coe±cient for leave-oneout cross validation were 0.046 mg mL À1 and 0.9998 mg mL À1 for TCP, and 0.235 mg mL À1 and 0.9986 mg mL À1 for Tris, respectively. All the models achieved highly accurate prediction e®ects, and the selected wavebands provided valuable references for designing specialized spectrometers. This study provided a valuable reference for further application of the proposed methods to TCP fermentation broth and to other spectroscopic analysis¯elds.

Wavelength Selection Method Based on Absorbance Value Optimization to Near-Infrared Spectroscopic Analysis

“…These local optimal solutions corresponded to the case where only the saturation region with high absorption was eliminated. Similar works can be found in previous studies [12,17,21,23]. However, compared with the global optimal solution, the predictive performance of the local optimal solution was poor.…”

“…The parameters of SG smoothing include order of derivatives (d), degree of polynomial (p), and number of smoothing points (m, odd). In a previous study, 21 the SG mode with first-order derivative, second-degree polynomial, and 33 smoothing points (d 1, p 2, and m 33) were used, and the prediction effect of PLS model for the human serum samples was improved. The SG mode (d 1, p 2, and m 33) was attempted in the PLS models of TC and TG.…”

“…In our previous study [21], an optimization algorithm was designed to determine the appropriate upper bound of absorbance and thus avoid the saturation region with high absorption. After the high absorbance wavebands were eliminated, a combination of separate wavebands was obtained and then used for further wavelength selection.…”

“…The AVO-PLS provides a novel approach for multi-band selection, which achieves simultaneous optimization for the lower and upper bounds of absorbance. Therefore, in terms of the algorithm, AVO-PLS is an improvement of the previous method that only avoided high absorption regions [21].…”