Application of near infrared spectroscopy and real time release testing combined with statistical process control charts for on-line quality control of industrial concentrating process of traditional Chinese medicine “Jinyinhua”

Abstract

Concentrating process is an important unit operation during the manufacture of Lonicerae Japonicae Flos (LJF, “Jinyinhua” in Chinese) products. Near infrared (NIR) spectroscopy and real time release testing (RTRT) combined with statistical process control (SPC) methods were presented for on-line monitoring of concentrating and developing quality control strategy for the final LJF concentrates. An automatic NIR detection (AND) device was designed and has proven effective to eliminate the influence of bubble, solid impurity and flow of the concentrates on NIR spectra. Partial least squares (PLS) models were constructed for on-line determination of neochlorogenic acid (NCA), chlorogenic acid (CA), cryptochlorogenic acid (CCA), density and water content, which provided real-time data and exhibited satisfactory predictive abilities. SPC tools, including univariate Shewhart, multivariate Hotelling T2 and squared prediction error (SPE), were compared and applied for RTRT. The results of RTRT showed that the releasing criteria for final LJF concentrates were as follows: 1.09 mg/g < NCA < 1.53 mg/g, 10.00 mg/g < CA < 13.44 mg/g, 1.71 mg/g < CCA < 2.43 mg/g, 1.10 g/ml < density < 1.14 g/ml, 64.07% < water content < 72.99% and SPE result < 0.04. Shewhart and SPE charts have proven to be useful in detecting abnormalities and releasing normal batches. This work demonstrated the effectiveness of NIR and RTRT combined with SPC charts in on-line quality control of industrial concentrating process of traditional Chinese medicine.