| Quality control is one of the most important factors for ensuring the safety and efficacy of traditional Chinese medicine(TCM).However,the analysis of TCM still encounters some challenges because of the diversity and complexity of the chemical components and the significant difference in the content of components.Chromatography and its united technology are essential for studying the properties and quality control of TCM because of their high sensitivity and high efficiency.High performance liquid chromatography with charged aerosol detection(HPLC-CAD)has a broad research and application prospect in the analysis of TCM with the advantages such as high sensitivity and reproducibility,wide detection range,high universality of response independent of chemical structure,and simplicity of operation.However,there has been less research on the HPLC-CAD methods of TCM and there are still some problems hindering the practical application of these methods.For example,the optimization of multiple evaluation metrics in developing HPLC-CAD methods for TCM is complex and challenging.Some conventional HPLC-CAD fingerprint methods were difficult to transfer because of their plentiful influencing factors.Moreover,the peak weights of the conventional similarity analysis algorithm were unreasonably assigned.The linear range of the HPLC-CAD standard curve for TCM analysis was needs to be optimized.In addition,the CAD response is influenced by the organic phase content,which limits the application of the characteristic of the CAD response uniformity.In this work,we provided theoretical and technical support to solve these defects and problems to promote the widespread application of HPLC-CAD technology in TCM.The main contents and achievements of this study are summarized as follows.1.With the high computational cost of the range of operational parameters based on probability-based method due to many evaluating indicators of the HPLC-CAD method for TCM,the order preference by similarity to ideal solution method was proposed for the comprehensive index optimization of the HPLC-CAD method for the saponin determination of Shengmai capsules.In contrast to Derringer’s desirability function method,this method may be more able to reflect the comprehensive influence of multiple indicators.The model prediction performance indexes were used as weights to guarantee the objective and reasonable contribution of each response variable.The method could reduce the load of calculation of the optimized ranges of operating parameters and promote the efficiency of developing the HPLC-CAD method for TCM.2.A chromatographic fingerprint method of Shengmai capsules was established effectively using tandem ultraviolet detection and CAD.A peak weighting algorithm was also proposed for the similarity analysis of the fingerprint.Definitive screening design was used to optimize the chromatographic conditions.And the optimized ranges of operating parameters were calculated using the Monte-Carlo method.In addition,the peak weights of the conventional similarity analysis methods were unreasonably assigned.A peak weighting algorithm that involved the relative correction factor and fingerprint peak variability was also proposed and applied for the similarity analysis of the HPLCUV/CAD fingerprint.The proposed weighting algorithm improves the sensitivity of distinguishing batch-to-batch quality differences of small sample data sets with similarity analysis methods.3.The optimization strategy of power function value combined with power law was proposed based on signal processing.The power function value was first optimized based on an empirical model in developing the HPLC-CAD method for the carbohydrate determination of Qishen Yiqi Dripping Pills.Then an optimization strategy of power function value combined with power law was proposed for multi-component determination simultaneously.Furthermore,the model performance of the least square method,weighted least squares methods,second-order polynomial fitting method,and the logarithmic curve-fitting method was evaluated and compared.The linear range of the standard curve by selecting optimal PFV and power law was 2.7 times greater than that of the instrument’s default values of PFV and power law.And the model uncertainty was reduced under the optimal conditions.In addition,the strategy of power functions and power law optimization combined with the logarithmic curve-fitting method could obtain more outstanding model fitting performance and have a better application prospect for research-oriented work.4.A HPLC-CAD-QAMS(quantitative analysis of multi-components by single marker)approach was established based on inverse gradient compensation technology of dual gradient liquid chromatography.And the crucial factors that affect the performance of the method were investigated comprehensively.First,Chromatographic conditions were optimized by a definitive screening design.Next,a new method to select the internal reference standards was successfully introduced based on the Pearson correlation coefficients of the response factors.Then,the multi-point method was selected to calculate the relative correction factors by comparison.The influence of the property of the analytes on the relative correction factor was investigated.A robustness test was conducted with a Plackett-Burman design.The HPLC-CAD-QAMS method was successfully established and applied to analyze accurately multi-class components of Qishen Yiqi Dripping Pills.5.To promote the popularization and application of inverse gradient compensation technology,the gradient-compensated flow path was constructed with an independent liquid chromatography pump to establish the HPLC-CAD-QAMS approach.Threedimensional response surfaces were constructed using raw data,thus showing the relationship between detector response,analyte concentration,and organic solvent content in the mobile phase.The relationship between the method parameters that influenced the solvent compensation performance and the method evaluation criteria were modelled using a Box-Behnken experimental design.Then three probability-based methods for calculating the optimized ranges of operating parameters were compared,namely the parameter perturbation simulation method,experimental error simulation method,and Bootstrapping method.Finally,the HPLC-CAD-QAMS method for the carbohydrate determination of Qishen Yiqi Dripping Pills was successfully established.The gradient compensation flow path,which played a good solvent compensation effect within a certain range of the organic content,promoted the wide application of the HPLCCAD-QAMS method of TCM. |
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