Near-Infrared Spectroscopy as an Analytical Process Technology for the On-Line Quantification of Water Precipitation Processes during Danhong Injection

Determination of Chinese hamster ovary (CHO) cell densities and antibody titers from small volumes of cell culture supernatants using multivariate analysis and partial least squares regression of UV-Vis spectra

Antibody titer and viable cell density (VCD) are two important parameters that need to be closely monitored during the process of cell line development and manufacturing of therapeutic antibodies. Typically, determination of each parameter requires 10–100 μL of supernatant sample, which is not suitable for small scale cultivation. In this study, we demonstrated that as low as 2 μL of culture supernatants were sufficient for the analysis using UV-Vis spectrum assisted with partial least squares (PLS) model. The results indicated that the optimal PLS models could be used to predict antibody titer and VCD with the linear relationship between reference values and predicted values at R² values ranging from 0.8 to > 0.9 in supernatant samples obtained from four different single clones and in polyclones that were cultured in various selection stringencies. Then, the percentage of cell viability and productivity were predicted from a set of samples of polyclones. The results indicated that while all predicted % cell viability were very similar to the actual value at RSEP value of 6.7 and R² of 0.8908, the predicted productivity from 14 of 18 samples were closed to the reference measurements at RSEP value of 22.4 and R² of 0.8522. These results indicated that UV-Vis combined with PLS has potential to be used for monitoring antibody titer, VCD, and % cell viability for both online and off-line therapeutic production process.

Monitoring of CO2 Absorption Solvent in Natural Gas Process Using Fourier Transform Near-Infrared Spectrometry

The analytical methods for the determination of the amine solvent properties do not provide input data for real-time process control and optimization and are labor-intensive, time-consuming, and impractical for studies of dynamic changes in a process. In this study, the potential of nondestructive determination of amine concentration, CO₂ loading, and water content in CO₂ absorption solvent in the gas processing unit was investigated through Fourier transform near-infrared (FT-NIR) spectroscopy that has the ability to readily carry out multicomponent analysis in association with multivariate analysis methods. The FT-NIR spectra for the solvent were captured and interpreted by using suitable spectra wavenumber regions through multivariate statistical techniques such as partial least square (PLS). The calibration model developed for amine determination had the highest coefficient of determination (R²) of 0.9955 and RMSECV of 0.75%. CO₂ calibration model achieved R² of 0.9902 with RMSECV of 0.25% whereas the water calibration model had R² of 0.9915 with RMSECV of 1.02%. The statistical evaluation of the validation samples also confirmed that the difference between the actual value and the predicted value from the calibration model was not significantly different and acceptable. Therefore, the amine, CO₂, and water models have given a satisfactory result for the concentration determination using the FT-NIR technique. The results of this study indicated that FT-NIR spectroscopy with chemometrics and multivariate technique can be used for the CO₂ solvent monitoring to replace the time-consuming and labor-intensive conventional methods.

Rapid quantitation and identification of the chemical constituents in Danhong Injection by liquid chromatography coupled with orbitrap mass spectrometry

Danhong Injection (DHI) is a Chinese medicine patent drug to treat cardiovascular diseases. It is derived from the herbal medicines Dan-shen and Hong-hua. The bioactive compounds of DHI are polar phenolic acids and flavonoid glycosides. Thus far, the contents of major compounds in DHI are not well understood, and the identification of minor compounds lacks rapid methods. In this work, quantitative and qualitative analyses of DHI compounds were performed using ultra-high performance liquid chromatography coupled with orbitrap mass spectrometry (UHPLC/orbitrap-MS). DHI was separated on an Acquity HSS T3 column (1.8 μm, 100 mm × 2.1 mm) and eluted with acetonitrile-water (containing 0.1% formic acid) to determine the contents of 12 compounds within 6 min. The method was fully validated according to the ICH guidance. To identify the minor compounds, an ion statistics-based strategy was used to dig for 4 filtering ions and 6 diagnostic ions from 22 reference standards. A total of 117 compounds, including 76 phenolic acids, 20 flavonoids, and 21 other compounds were tentatively identified. The poor stability of salvianolic acid A upon storage was also discussed.

Rapid Determination of Saponins in the Honey-Fried Processing of Rhizoma Cimicifugae by Near Infrared Diffuse Reflectance Spectroscopy

OBJECTIVE

A model of Near Infrared Diffuse Reflectance Spectroscopy (NIR-DRS) was established for the first time to determine the content of Shengmaxinside I in the honey-fried processing of Rhizoma Cimicifugae.

METHODS

Shengmaxinside I content was determined by high-performance liquid chromatography (HPLC), and the data of the honey-fried processing of Rhizoma Cimicifugae samples from different batches of different origins by NIR-DRS were collected by TQ Analyst 8.0. Partial Least Squares (PLS) analysis was used to establish a near-infrared quantitative model.

RESULTS

The determination coefficient R² was 0.9878. The Cross-Validation Root Mean Square Error (RMSECV) was 0.0193%, validating the model with a validation set. The Root Mean Square Error of Prediction (RMSEP) was 0.1064%. The ratio of the standard deviation for the validation samples to the standard error of prediction (RPD) was 5.5130.

CONCLUSION

This method is convenient and efficient, and the experimentally established model has good prediction ability, and can be used for the rapid determination of Shengmaxinside I content in the honey-fried processing of Rhizoma Cimicifugae.

Highly efficient oxygen evolution from CoS2/CNT nanocomposites via a one-step electrochemical deposition and dissolution method

The oxygen evolution reaction (OER) has been viewed as a critical step in electrochemical energy conversion and storage devices. However, searching for cheap and efficient OER electrocatalysts still remains an urgent task. Herein, we develop a new strategy involving a one-step electrochemical deposition and dissolution method to fabricate hydrophilic porous CoS₂/carbon nanotube (CNT) composites (CNT-CoS₂). X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy measurements confirm the formation of hydrophilic groups on the surface of the porous CoS₂ during electrochemical oxidation. Our design holds several advantages. The electricity conductivity of CoS₂ is increased by introducing CNTs as a conductive substrate. The porous nanostructures of CoS₂ increase its surface area, and provide paths to promote charge and reactant transfer. The active edge sites modified with hydrophilic groups can increase the content of electrolyte-electrode contact points, increasing the intrinsic catalytic performance of CoS₂. These factors allow CNT-CoS₂ to achieve a low onset potential of 1.33 V vs. RHE, a stable current density (j) of 10 mA cm^-2 at an overpotential of 290 mV, and excellent stability under alkaline conditions compared to that of IrO₂. The comprehensive performance of the CNT-CoS₂ electrocatalyst is comparable to or better than that of any reported noble metal-free OER catalyst, even RuO₂ and IrO₂. This facile synthesis strategy involving synchronous electrochemical deposition and dissolution should be easily adapted for large-scale water electrolysis.

S,N co-doped carbon nanotubes decorated with ultrathin molybdenum disulfide nanosheets with highly electrochemical performance

A facile route for the synthesis of a type of composite nanotube, namely S,N co-doped carbon nanotubes decorated with molybdenum disulfide nanosheets (CP/MoS₂), is now reported. The number of nanosheets for MoS₂ can be easily tuned by changing the templates with different ratios of N and S. When evaluated as an anode material for lithium-ion batteries, the CP/MoS₂ nanotubes show a high specific capacity of around 1500 mA h g^-1 at the current density of 50 mA g^-1, excellent cycling stability up to 750 cycles at the current density of 1 A g^-1, and superior rate performance.

Half and full sodium-ion batteries based on maize with high-loading density and long-cycle life

Sodium-ion batteries are especially attractive in the field of sustainable and cost-effective energy storage devices as promising alternatives to lithium-ion batteries. In this work, a lamellar carbon anode derived from biomass byproduct maize husks (LCMH) and a suitable NASICON structured Na3V2(PO4)3 cathode are utilized to assemble a full sodium-ion battery, which exhibits an extremely long cycle life of ∼1000 cycles and a high voltage of 4.1 V. More importantly, a stable reversible capacity of 239.6 mA h g(-1) for the LCMH anode is obtained, along with an ultra-long cycling performance of ∼5000 cycles and a high mass loading density of 8.31 mg cm(-2). Significantly, in-situ X-ray diffraction measurements are introduced to reveal the Na-storage mechanism and structure evolution upon battery cycling. This strategy provides a brand-new direction for building advanced electrode materials for full sodium-ion batteries.