title: On-line quantitative monitoring of liquid-liquid extraction of Lonicera japonica and Artemisia annua using near-infrared spectroscopy and chemometrics.
abstract: BACKGROUND
  Liquid-liquid extraction of Lonicera japonica and Artemisia annua (JQ) plays a significant role in manufacturing Reduning injection. Many process parameters may influence liquid-liquid extraction and cause fluctuations in product quality.
  
  
  OBJECTIVE
  To develop a near-infrared (NIR) spectroscopy method for on-line monitoring of liquid-liquid extraction of JQ.
  
  
  METHODS
  Eleven batches of JQ extraction solution were obtained, ten for building quantitative models and one for assessing the predictive accuracy of established models. Neochlorogenic acid (NCA), chlorogenic acid (CA), cryptochlorogenic acid (CCA), isochlorogenic acid B (ICAB), isochlorogenic acid A (ICAA), isochlorogenic acid C (ICAC) and soluble solid content (SSC) were selected as quality control indicators, and measured by reference methods. NIR spectra were collected in transmittance mode. After selecting the spectral sub-ranges, optimizing the spectral pretreatment and neglecting outliers, partial least squares regression models were built to predict the content of indicators. The model performance was evaluated by the coefficients of determination (R (2)), the root mean square errors of prediction (RMSEP) and the relative standard error of prediction (RSEP).
  
  
  RESULTS
  For NCA, CA, CCA, ICAB, ICAA, ICAC and SSC, R (2) was 0.9674, 0.9704, 0.9641, 0.9514, 0.9436, 0.9640, 0.9809, RMSEP was 0.0280, 0.2913, 0.0710, 0.0590, 0.0815, 0.1506, 1.167, and RSEP was 2.32%, 4.14%, 3.86%, 5.65%, 7.29%, 6.95% and 4.18%, respectively.
  
  
  CONCLUSIONS
  This study demonstrated that NIR spectroscopy could provide good predictive ability in monitoring of the content of quality control indicators in liquid-liquid extraction of JQ.
authors.affiliation: College of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100102, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Wu
authors.affiliation: College of Pharmaceutical Science, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Jin
authors.affiliation: National Key Laboratory of Pharmaceutical New Technology for Chinese Medicine, Kanion Pharmaceutical Corporation, Lianyungang, 222000, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Pharmaceutical New Technology for Chinese Medicine, Kanion Pharmaceutical Corporation, Lianyungang, 222000, China.
authors.forename: Qi-An
authors.initials: QA
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Pharmaceutical New Technology for Chinese Medicine, Kanion Pharmaceutical Corporation, Lianyungang, 222000, China.
authors.forename: Jianxiong
authors.initials: J
authors.lastname: Wu
authors.affiliation: National Key Laboratory of Pharmaceutical New Technology for Chinese Medicine, Kanion Pharmaceutical Corporation, Lianyungang, 222000, China.
authors.forename: Yu-An
authors.initials: YA
authors.lastname: Bi
authors.affiliation: National Key Laboratory of Pharmaceutical New Technology for Chinese Medicine, Kanion Pharmaceutical Corporation, Lianyungang, 222000, China.
authors.forename: Zhengzhong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100102, China ; National Key Laboratory of Pharmaceutical New Technology for Chinese Medicine, Kanion Pharmaceutical Corporation, Lianyungang, 222000, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
keywords: liquid-liquid extraction; near-infrared spectroscopy; on-line monitoring; partial least squares