Progress and prediction of multicomponent quantification in complex systems with practical LC-UV methods

Complex systems exist widely,including medicines from natural products,functional foods,and biological samples.The biological activity of complex systems is often the result of the synergistic effect of multiple components.In the quality evaluation of complex samples,multicomponent quantitative analysis(MCQA)is usually needed.To overcome the difficulty in obtaining standard products,scholars have proposed achieving MCQA through the“single standard to determine multiple components(SSDMC)”approach.This method has been used in the determination of multicomponent content in natural source drugs and the analysis of impurities in chemical drugs and has been included in the Chinese Pharmacopoeia.Depending on a convenient(ultra)high-performance liquid chromatography method,how can the repeatability and robustness of the MCQA method be improved?How can the chromatography conditions be optimized to improve the number of quantitative components?How can computer software technology be introduced to improve the efficiency of multicomponent analysis(MCA)?These are the key problems that remain to be solved in practical MCQA.First,this review article summarizes the calculation methods of relative correction factors in the SSDMC approach in the past five years,as well as the method robustness and accuracy evaluation.Second,it also summarizes methods to improve peak capacity and quantitative accuracy in MCA,including column selection and twodimensional chromatographic analysis technology.Finally,computer software technologies for predicting chromatographic conditions and analytical parameters are introduced,which provides an idea for intelligent method development in MCA.This paper aims to provide methodological ideas for the improvement of complex system analysis,especially MCQA.

Field Load Test Based SHM System Safety Standard Determination for Rigid Frame Bridge

The deteriorated continuous rigid frame bridge is strengthened by external prestressing. Static loading tests wereconducted before and after the bridge rehabilitation to verify the effectiveness of the rehabilitation process. Thestiffness of the repaired bridge is improved, and the maximum deflection of the load test is reduced from 37.9 to27.6 mm. A bridge health monitoring system is installed after the bridge is reinforced. To achieve an easy assessmentof the bridge’s safety status by directly using transferred data, a real-time safety warning system is createdbased on a five-level safety standard. The threshold for each safety level will be determined by theoretical calculationsand the outcomes of static loading tests. The highest risk threshold will be set at the ultimate limit statevalue. The remaining levels, namely middle risk, low risk, and very low risk, will be determined usingreduction coefficients of 0.95, 0.9, and 0.8, respectively.

An entirely new approach based on remote sensing data to calculate the nitrogen nutrition index of winter wheat

The nitrogen nutrition index(NNI)is a reliable indicator for diagnosing crop nitrogen(N)status.However,there is currently no specific vegetation index for the NNI inversion across multiple growth periods.To overcome the limitations of the traditional direct NNI inversion method(NNI_(T1))of the vegetation index and traditional indirect NNI inversion method(NNI_(T2))by inverting intermediate variables including the aboveground dry biomass(AGB)and plant N concentration(PNC),this study proposed a new NNI remote sensing index(NNI_(RS)).A remote-sensing-based critical N dilution curve(Nc_(_RS))was set up directly from two vegetation indices and then used to calculate NNI_(RS).Field data including AGB,PNC,and canopy hyperspectral data were collected over four growing seasons(2012–2013(Exp.1),2013–2014(Exp.2),2014–2015(Exp.3),2015–2016(Exp.4))in Beijing,China.All experimental datasets were cross-validated to each of the NNI models(NNI_(T1),NNI_(T2)and NNI_(RS)).The results showed that:(1)the NNI_(RS)models were represented by the standardized leaf area index determining index(sLAIDI)and the red-edge chlorophyll index(CI_(red edge))in the form of NNI_(RS)=CI_(red edge)/(a×sLAIDI~b),where"a"equals 2.06,2.10,2.08 and 2.02 and"b"equals 0.66,0.73,0.67 and 0.62 when the modeling set data came from Exp.1/2/4,Exp.1/2/3,Exp.1/3/4,and Exp.2/3/4,respectively;(2)the NNI_(RS)models achieved better performance than the other two NNI revised methods,and the ranges of R2 and RMSE were 0.50–0.82 and 0.12–0.14,respectively;(3)when the remaining data were used for verification,the NNI_(RS)models also showed good stability,with RMSE values of 0.09,0.18,0.13 and 0.10,respectively.Therefore,it is concluded that the NNI_(RS)method is promising for the remote assessment of crop N status.

A SERIES OF STRATEGIES FOR SOLVING THE SHORTAGE OF REFERENCE STANDARDS FOR MULTI-COMPONENTS DETERMINATION OF TRADITIONAL CHINESE MEDICINE

The shortage of reference standards has become the bottleneck of quality control of TCMs.In this study,a series of strategies,including one single reference standard to determine multi-compounds(SSDMC),quantitative analysis by standardized reference extract(QASRE),and quantitative nuclear magnetic resonance

A feasible,economical,and accurate analytical method for simultaneous determination of six alkaloid markers in Aconiti Lateralis Radix Praeparata from different manufacturing sources and processing ways

Aconiti Lateralis Radix Praeparata(Fuzi) is a commonly used traditional Chinese medicine in clinic for its potency in restoring yang and rescuing from collapse. Aconiti alkaloids, mainly including monoester-diterpenoidaconitines(MDAs) and diester-diterpenoidaconitines(DDAs), are considered to act as both bioactive and toxic constituents. In the present study, a feasible, economical, and accurate HPLC method for simultaneous determination of six alkaloid markers using the Single Standard for Determination of Multi-Components(SSDMC) method was developed and fully validated. Benzoylmesaconine was used as the unique reference standard. This method was proven as accurate(recovery varying between 97.5%-101.8%, RSD < 3%), precise(RSD 0.63%-2.05%), and linear(R > 0.999 9) over the concentration ranges, and subsequently applied to quantitative evaluation of 62 batches of samples, among which 45 batches were from good manufacturing practice(GMP) facilities and 17 batches from the drug market. The contents were then analyzed by principal component analysis(PCA) and homogeneity test. The present study provided valuable information for improving the quality standard of Aconiti Lateralis Radix Praeparata. The developed method also has the potential in analysis of other Aconitum species, such as Aconitum carmichaelii(prepared parent root) and Aconitum kusnezoffii(prepared root).

Simultaneous Determination of Seven Components in Gamboge and Its Processed Products Using a Single Reference Standard

Objective To establish a quality control method for simultaneous determination of multiple components in gamboge. Methods A single reference standard for the determination of multiple components （SSDMC） with HPLC was proposed. Seven major components of gamboge including gambogenic acid （S）, β-morellic acid （C1）, 2R-30-hydroxygambogic acid （C2）, isogambogenic acid （C3）, gambogellic acid （C4）, 2R-gambogic acid （C5）, and 2S-gambogic acid （C6） were simultaneously analyzed using gambogenic acid as reference standard. The credibility and feasibility of SSDMC method were validated with respect to linearity, limits of detection and quantification, precision, stability, repeatability, accuracy, ruggedness, and robustness. The relative conversion factors （RCFs） of S and C1-6 were calculated. Twelve batches of gamboge including crude and processed products were successfully analyzed by applying the SSDMC and traditional external standard （ES） methods. Results The SSDMC method was credible and feasible. The RCFs of S and C1-6 were 1.000, 0.913, 0.864, 1.064, 0.777, 0.921, and 0.919, respectively. No significant difference was observed in the contents of the seven components between SSDMC and ES methods. The heat-processing technique caused a reduction in the seven components. Conclusion SSDMC is a simple, reliable, and effective method for the analysis of the complex multiple components in gamboge, and it is also a practical and economical approach.

Simultaneous Determination of Four Anthraquinones in Polygoni Multiflori Radix with Single Reference Standard by High Performance Liquid Chromatography

Objective: To establish a rapid, accurate and reliable analytical method for the simultaneous determination of four major anthraquinones in Polygoni Multiflori Radix(PMR) using single reference standard.Methods: The four components including emodin-8-O-β-D-(EMG), physcion-8-O-β-D-glucoside, emodin and physcion were separated on an ODS C18 column within 13 min and detected at 280 nm. Emodin was selected as the reference standard, and the response factor for each analyte with respect to emodin were calculated. Robustness were also tested including different columns, equipments, temperatures, detection wavelengths, and other chromatographic conditions which might influence stability of response factors.Results: The method was validated in terms of linearity(r^2> 0.9995), LOQs(0.820–3.05 ng/m L), LODs(0.180–0.920 ng/m L), precision,accuracy(95.8–103.6%, RSD < 2.80%) and stability. A total of 40 batches of PMR were analyzed and the results were found to have no statistically significant differences compared with those obtained using the external standard method.Conclusion: This work provided a single standard to determine multi-components method for quantitation of four anthraquinones in PMR,which could be applied in the quality control of this herbal drug.