Jianbo Chen

Chemical profiling and adulteration screening of Aquilariae Lignum Resinatum by Fourier transform infrared (FT-IR) spectroscopy and two-dimensional correlation infrared (2D-IR) spectroscopy

As a kind of expensive perfume and valuable herb, Aquilariae Lignum Resinatum (ALR) is often adulterated for economic motivations. In this research, Fourier transform infrared (FT-IR) spectroscopy is employed to establish a simple and quick method for the adulteration screening of ALR. First, the principal chemical constituents of ALR are characterized by FT-IR spectroscopy at room temperature and two-dimensional correlation infrared (2D-IR) spectroscopy with thermal perturbation. Besides the common cellulose and lignin compounds, a certain amount of resin is the characteristic constituent of ALR. Synchronous and asynchronous 2D-IR spectra indicate that the resin (an unstable secondary metabolite) is more sensitive than cellulose and lignin (stable structural constituents) to the thermal perturbation. Using a certified ALR sample as the reference, the infrared spectral correlation threshold is determined by 30 authentic samples and 6 adulterated samples. The spectral correlation coefficient of an authentic ALR sample to the standard reference should be not less than 0.9886 (p=0.01). Three commercial adulterated ALR samples are identified by the correlation threshold. Further interpretation of the infrared spectra of the adulterated samples indicates the common adulterating methods - counterfeiting with other kind of wood, adding ingredient such as sand to increase the weight, and adding the cheap resin such as rosin to increase the content of resin compounds. Results of this research prove that FT-IR spectroscopy can be used as a simple and accurate quality control method of ALR.

Rapid and automatic chemical identification of the medicinal flower buds of Lonicera plants by the benchtop and hand-held Fourier transform infrared spectroscopy

With the utilization of the hand-held equipment, Fourier transform infrared (FT-IR) spectroscopy is a promising analytical technique to minimize the time cost for the chemical identification of herbal materials. This research examines the feasibility of the hand-held FT-IR spectrometer for the on-site testing of herbal materials, using Lonicerae Japonicae Flos (LJF) and Lonicerae Flos (LF) as examples. Correlation-based linear discriminant models for LJF and LF are established based on the benchtop and hand-held FT-IR instruments. The benchtop FT-IR models can exactly recognize all articles of LJF and LF. Although a few LF articles are misjudged at the sub-class level, the hand-held FT-IR models are able to exactly discriminate LJF and LF. As a direct and label-free analytical technique, FT-IR spectroscopy has great potential in the rapid and automatic chemical identification of herbal materials either in laboratories or in fields. This is helpful to prevent the spread and use of adulterated herbal materials in time.

Direct and model-free detection of carbohydrate excipients in traditional Chinese medicine formula granules by ATR-FTIR microspectroscopic imaging

AbstractA formula granule is a traditional Chinese medicine preparation made from the decoction of a single herbal medicinal. Because of the flexibility for combination and the convenience for utilization, formula granules are becoming popular in clinical applications. However, the efficacy and safety of commercial formula granules often suffer from the improper addition of carbohydrate excipients. Therefore, the detection of carbohydrate excipients is indispensable for the quality control of formula granules. FTIR spectroscopy has been used for the detection of carbohydrate excipients in formula granules. But the overlapped absorption signals limit the sensitivity and specificity of detection. Besides, a large number of multivariate calibration models are needed for quantitative determination. To overcome the above disadvantages, this research utilizes FTIR microspectroscopy for the model-free and universal detection of carbohydrate excipients in formula granules. Using ATR-FTIR imaging, excipient particles and herbal extract particles in formula granules can be measured individually, which resolves the absorption signals of excipients and herbal extract spatially and thus improves the sensitivity and specificity of detection. The content of excipients can be estimated directly from the number of excipient particles, which is robust to the variations of herb extracts and free of calibration models. The case study of Gardeniae Fructus formula granules shows the potential of FTIR microspectroscopy in the direct and rapid detection of carbohydrate excipients in formula granules. Graphical AbstractExcipient particles in TCM formula granules can be measured and recognized individually by FTIR microspectroscopy

Rapid identification and quantification of carbohydrate excipients in Gardeniae Fructus formula granules by ATR-FTIR spectroscopy

Formula granule is a traditional Chinese medicine (TCM) preparation usually made from the decoction of a single herbal medicinal by spray drying. It is easy to make a TCM formula decoction by dissolving multiple formula granules in hot water, instead of boiling the herbal medicinals in water for hours. The flexibility and convenience make formula granules more and more popular in TCM clinical applications. However, the efficacy and safety of commercial formula granules often suffer from the excessive addition of carbohydrate excipients. In this research, Fourier transform infrared (FTIR) spectroscopy is used for the simple and rapid detection of carbohydrate excipients in formula granules of Gardeniae Fructus (GF). Using the attenuated total reflection (ATR) accessory, formula granules can be measured directly free of pretreatments or chemical reagents. Lactose and sucrose in simulated GF granules can be identified by the characteristic peaks in the second derivative spectra when the weight concentration of the excipient is 10%. Dextrin, which is the most common excipient in commercial formula granules, in simulated GF granules can be quantified by the partial least squares calibration model when the weight concentration of dextrin is above 5%. The excessive addition of dextrin is found in some commercial GF formula granules. This research shows the potential of ATR-FTIR spectroscopy in the rapid, green, and low-cost detection of carbohydrate excipients for the quality control of GF formula granules and analogues.

Evaluation on the concentration change of paeoniflorin and glycyrrhizic acid in different formulations of Shaoyao-Gancao-Tang by the tri-level infrared macro-fingerprint spectroscopy and the whole analysis method

As a kind of common prescriptions, Shaoyao-Gancao-Tang (SGT) contains two Chinese herbs with four different proportions which have different clinical efficacy because of their various components. In order to investigate the herb-herb interaction mechanisms, we used the method of tri-level infrared macro-fingerprint spectroscopy to evaluate the concentration change of active components of four SGTs in this research. Fourier transform infrared spectroscopy (FT-IR) and Second derivative infrared spectroscopy (SD-IR) can recognize the multiple prescriptions directly and simultaneously. 2D-IR spectra enhance the spectral resolution and obtain much new information for discriminating the similar complicated samples of SGT. Furthermore, the whole analysis method from the analysis of the main components to the specific components and the relative content of the components may evaluate the quality of TCM better. Then we concluded that paeoniflorin and glycyrrhizic acid were the highest proportion in active ingredients in SGT-12:1 and the lowest one in SGT-12:12, which matched the HPLC-DAD results. It is demonstrated that the method composed by the tri-level infrared macro-fingerprint spectroscopy and the whole analysis can be applicable for effective, visual and accurate analysis and identification of very complicated and similar mixture systems of traditional Chinese medicine.

A Simple and Portable Screening Method for Adulterated Olive Oils Using the Hand-Held FTIR Spectrometer and Chemometrics Tools: Adulteration screening of olive oils …

Extra virgin olive oil has been one of the most common targets for economically motivated food adulteration. This research employed the hand-held FTIR spectrometer to develop the simple and portable screening methods for extra virgin olive oils adulterated with other cheaper vegetable oils. With the help of the ATR probe and chemometrics tools, oil samples can be measured directly without any pretreatment, then the spectra can be interpreted automatically to determine the possibility of adulteration and estimate the content of adulterant oil. A feasibility study of the hand-held FTIR screening method was carried out using olive oils adulterated with canola oil, peanut oil, corn oil, soybean oil, and sunflower oil. The SIMCA model using the hand-held FTIR spectra can identify different kinds of vegetable oils correctly and recognize olive oils with not less than 10% of adulterant oils. Meanwhile, the content of adulterant oil in the range of 5% to 45% can be estimated by the PLS model using the hand-held FTIR spectra within an error of 3%. This research shows the potential of the hand-held FTIR technique in the rapid and field screening of olive oils adulterated with some cheaper vegetable oils. PRACTICAL APPLICATION This research provide a rapid and automatic detection method for olive oils adulterated with other cheaper vegetable oils. An oil sample can be measured directly within one minute, and the hand-held instrument can be used anywhere needed.

Crystallinity of regenerated cellulose from [Bmim]Cl dependent on the hydrogen bond acidity/basicity of anti-solvents

Cellulose, regarded as a potential sustainable resource for the future, can dissolve and regenerate in ionic liquids (ILs) upon adding anti-solvents. Improving the regeneration conditions, like changing the anti-solvents, could optimize the properties of regenerated cellulose-based materials. Previous studies pointed out that the diffusion processes of anti-solvents plays a significant role in the determination of the properties of regenerated cellulose fibers/films. However, the cellulose regeneration mechanism from ILs has not been clarified. Here, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was introduced to monitor the molecular diffusion processes of four anti-solvents in situ. The crystallinity of regenerated cellulose showed a negative correlation with respect to the diffusion coefficient. In addition, the interaction of imidazolium cations and anti-solvent molecules was evaluated from the peak shifting during the diffusion processes. Furthermore, Taft and Kamlet scales were used to quantify the interaction between IL cations/anions and anti-solvent molecules, eliciting distinct cellulose regeneration paths in different anti-solvents.

Rapid and Integrated Quality Assessment of Organic-Inorganic Composite Herbs by FTIR Spectroscopy—Global Chemical Fingerprints Identification and Multiple Marker Components Quantification of Indigo Naturalis (Qing Dai)

This research aimed to develop an FTIR-based method for rapid and low-cost integrated quality assessment of organic-inorganic composite herbs, which are kinds of herbs composed of both organic and inorganic active ingredients or matrix components. A two-step quality assessment route was designed and verified using the example of Indigo Naturalis (Qing Dai). First, the FTIR spectra were used as global chemical fingerprints to identify the true and fake samples. Next, the contents of the organic and inorganic marker components were estimated by FTIR quantification models to assess the quality of the true samples. Using the above approaches, all the 56 true samples and five fake samples of Indigo Naturalis could be identified correctly by the correlation threshold of the FTIR chemical fingerprints. Furthermore, the FTIR calibration models provided an accurate estimation of the contents of marker components with respect to HPLC and inductively coupled plasma optical emission spectrometry (ICP-OES). The coefficients of determination (R2) for the independent validation of indigo, indirubin, and calcium were 0.977, 0.983, and 0.971, respectively. Meanwhile, the mean relative errors (MRE) for the independent validation of indigo, indirubin, and calcium were 2.2%, 2.4%, and 1.8%, respectively. In conclusion, this research shows the potential of FTIR spectroscopy for the rapid and integrated quality assessment of organic-inorganic composite herbs in both chemical fingerprints identification and marker components quantification.

Anti-solvents tuning cellulose nanoparticles through two competitive regeneration routes

In this work, cellulose nanoparticles regenerated by water, methanol, ethanol and n-propanol as the anti-solvents from ionic liquid solution were studied systematically. Crystallinity and enthalpy in cellulose degradation of the regenerated cellulose decreased in the order water > methanol > ethanol > n-propanol. Nevertheless, the thermal stability of the regenerated cellulose showed an opposite trend. In addition, morphology of regenerated cellulose changed sharply with the variation of anti-solvents. Moreover, we introduced Kamlet–Taft parameters of anti-solvents to analyze the crystallinity, enthalpy in cellulose degradation and thermal stability variation of regenerated cellulose. Hydrogen bond acidity and basicity of anti-solvent definitely drove the property variation of regenerated cellulose nanoparticles to opposite directions. Furtherly, we proposed two competitive cellulose regeneration routes, providing a reasonable explanation to the crystallinity, enthalpy in cellulose degradation and thermal stability variation of regenerated cellulose nanoparticles. Our work successfully demonstrate that H-bond acidity/basicity of anti-solvent could tune the property of regenerated cellulose nanoparticles, unveiling the competitive routes of cellulose regeneration.