Rapid determination of Scutellaria baicalensis extract by near infrared spectroscopy

In the determination of alcohol extract, NIR analysis technology can make the determination easier and faster Due to the wide range of substances and occasions suitable for NIR measurement, the technology has been widely used in drug quality control Objective to determine the content of alcohol extract in Scutellaria baicalensis Georgi by NIR and data analysis software Methods the partial least square method (PLS) was used to establish the calibration model between the results of baicalin price alcohol extract and NIR Results the results of internal cross validation and external test set samples showed that the correlation coefficient (R2) between the real value and the predicted value was 92.52, and the mean square deviation of internal validation RMSECV was 1.58% Conclusion the application of NIR is fast, convenient and accurate This method can be used in the rapid detection of the alcohol extract of Scutellaria baicalensis, and also has a certain reference value for the determination of other index components of traditional Chinese medicine Near infrared partial least square method for rapid determination of near infrared spectrum (NIR) region of Scutellaria baicalensis price extract according to ASTM definition refers to electromagnetic wave with wavelength in 780-2526nm range, which is the first non visible light region discovered by people [1], nearly 200 years ago [2] The NIR region is mainly caused by the overtone and group frequency of the vibration of chemical groups containing hydrogen The main functional groups in the NIR region are H-containing groups, including C-H (methyl, methylene, methoxy, carboxyl, aryl, etc.), hydroxy O-H, mercapto S-H, amino N-H (primary amine, secondary amine, tertiary amine and amine salt), etc The chemical basis of NIR quantitative analysis is the frequency doubling of these groups' stretching vibration and the combined frequency absorption of these groups' stretching vibration and bending vibration [3] Scutellaria baicalensis Georgi, a Labiatae plant, is mainly produced in Northeast China, Hebei, Shanxi, Henan, Shaanxi, Inner Mongolia and other places, with the largest output in Shanxi Province The price of Scutellaria baicalensis Georgi is bitter in taste and cold in nature It has the functions of clearing away heat, drying dampness, purging fire, detoxifying, hemostasis, and calming the fetus [4] The price of Scutellaria baicalensis Georgi is a kind of traditional Chinese medicine, which is widely used in clinical practice Therefore, the quality of the original medicine is related to the safety of clinical medication The content of price alcohol extract of Scutellaria baicalensis Georgi is one of the important indexes to control the quality of medicinal materials It is related to the paste rate of medicinal materials and reflects the overall quality of medicinal materials The determination of alcohol extract is of great significance to the production of pharmaceutical plants and personal use of drugs However, at present, the research and improvement of the method for the determination of alcohol extractives are slow The pretreatment of the method is time-consuming and cumbersome, and the analysis results lag behind, which affects the analysis speed NIR analysis technology is more suitable for large-scale production because of its real-time, online and nondestructive characteristics In this method, the extract of Scutellaria baicalensis Georgi was determined by NIR and chemometrics 1 equipment 1.1 instrument and reagent near-infrared spectrometer: vector22-nir Fourier transform near-infrared spectrometer of Brooke company; cs101-2d electric blast drying oven (Chongqing Sida Experimental Instrument Co., Ltd., a Sino foreign joint venture); ethanol is chromatographic pure 1.2 the price of Scutellaria baicalensis Georgi in the sample source experiment is from 10 provinces such as Inner Mongolia, Hubei, Henan, Shandong, Sichuan, Yunnan, Gansu, Anhui, Shanxi, etc the price of cultivated or wild Scutellaria baicalensis Georgi is identified as the price of Scutellaria baicalensis Georgi in Labiatae by Professor Chen Suiqing of Henan College of traditional Chinese medicine Root 2 Methods and results 2.1 the real value of the extract of Scutellaria baicalensis Georgi was determined by the method of Chinese Pharmacopoeia (2005 Edition) Take about 2G of Scutellaria baicalensis Georgi price raw material powder, weigh it accurately, put it into a conical flask of 100-250ml, add 50ml of dilute ethanol precisely, weigh it, after standing for 1h, continuously reflux the condenser tube, heat it to boiling, and keep it slightly boiling for 1H After cooling, take off the conical bottle, close the plug, weigh it again, make up the weight lost with thin alcohol, shake it well, filter it with a drying filter, accurately measure 25ml of the continuous filtrate, place it in a constant weight evaporating dish, evaporate it in a water bath, dry it at 105 ℃ for 3h, cool it in a dryer for 30min, and weigh it quickly and accurately The content (%) of alcohol soluble extract in the test sample was calculated by dry sample 2.2 near infrared spectroscopy (NIRS) was used to collect the price samples of Scutellaria baicalensis Georgi collected from 80 different places of origin and at different harvest times The samples were dried at 40 ℃, crushed and screened at 100 mesh About 5g of the screened sample powder was put into the quartz price sample cup, mixed evenly, gently flattened, and scanned according to the following experimental conditions: the sample was measured by integrating sphere diffuse reflection with a resolution of 8cm-1; the number of scans was 64 times; Scanning range: 12000-4000cm-1; temperature: 20 ℃; air humidity: 60% It can be seen from Fig 1 that the near-infrared original spectra of 80 samples are basically the same, and it is difficult to see the difference of spectral information of medicinal materials On the one hand, the near-infrared spectral bands are overlapped seriously, on the other hand, the composition of traditional Chinese medicine is complex, so it is difficult to distinguish them from the original near-infrared spectral bands 2.3 establishment of near-infrared quantitative model of Scutellaria baicalensis price medicine extract Choosing the appropriate band can improve the performance of the model After screening (see Table 1), the best wave band range corresponding to the extract content is 11995.9-7498.4cm-1 and 5450.2-4246.8cm-1 2.3.2 pretreatment Table 2 of spectral data is the comparison of RMSECV and R2 of various processed models after spectral data analysis Fig 2 shows the spectrum after preprocessing the original spectrum with vector normalization It can be seen from table 2 that RMSECV and R2 obtained by different spectral preprocessing methods with different index components are significantly different, among which vector normalization is the best After the necessary pretreatment of the original spectrum, the spectral information of the index components can be reflected more truly and carefully 2.3.3 establishment of quantitative model of leachables in this paper, the PLS method in brukeropus / quant22 quantitative analysis software is used for data processing, 70 samples are used as calibration sample set to establish the model, and 10 samples are used as prediction sample set The internal cross validation of RMSECV = 1.66 and R2 = 92.03 was carried out with the calibration sample set (see Figure 3), and the optimal principal component fraction was determined to be 7 (see Figure 4) The absolute error between the measured value and the real value of NIRS is between - 4% and 3.5% (see Figure 5) Among them, the real value refers to the result of sample determination by legal method in Pharmacopoeia; the measured value refers to the result of sample determination by near-infrared spectroscopy 2.3.4 validation of the quantitative model of leachables 8 samples are randomly selected from all 80 samples to form the test sample set to test the proposed model The average relative error of prediction set is 1.92% It can be seen that the prediction results are more accurate and the establishment of the model is successful 3 From the results of this experiment, it can be seen that the parameters of the quantitative model of leachables are RMSECV = 1.66, R2 = 92.03 R2 is the correlation coefficient The closer its value is to 1, the closer the real value is to the predicted value of the model, the higher the accuracy of the model will be RMSECV is the root mean square error of cross test The closer its value is to 0, the smaller the deviation of model prediction value is R2 and RMSECV are important parameters to evaluate the success of the model It can be seen from the experimental results that the relative deviation of prediction set is within 5% This method can be applied to the rapid detection of extracts of medicinal materials, which lays a foundation for a new way of drug analysis In the preprocessing of the model, the method of multiple scattering correction is selected, and each spectrum is linearly transformed to make it match the whole average spectrum best In the process of solid sample determination, there must be different degree of nonuniformity in the sample particles In order to eliminate the influence of particle nonuniformity, the multi-element scattering correction method is usually preferred in the determination of solid samples Because the composition of traditional Chinese medicine is very complex and contains many chemical components, there are many factors that affect the extract The near-infrared spectra of various chemical components inevitably overlap, which makes the analysis of the spectra very difficult Although we try to eliminate these effects by spectrum preprocessing and selecting appropriate waveband as much as possible, it is not possible to completely eliminate them Therefore, further experiments and explorations are needed.