Bao Qiong Li

An application of wavelet moments to the similarity analysis of three-dimensional fingerprint spectra obtained by high-performance liquid chromatography coupled with diode array detector

More and more the three-dimensional (3D) fingerprint spectra, which can be obtained by high performance liquid chromatography coupled with diode array detector (HPLC-DAD), are applied to the analysis of drugs and foods. A novel approach to the similarity analysis of traditional Chinese medicines (TCMs) was proposed based on the digital image processing using 3D HPLC-DAD fingerprint spectra. As the one of shape features of digital grayscale image, wavelet moments were employed to extract the shape features from the grayscale images of 3D fingerprint spectra of different Coptis chinensis samples, and used to the similarity analysis of these samples. Compared with the results obtained by traditional features including principal components and spectrum data under single-wavelength, our results represented the more reliable assessment. This work indicates that the better features of fingerprint spectra are more important than similarity evaluation methods. Wavelet moments, which possess multi-resolution specialty and the invariance property in image processing, are more effective than traditional spectral features for the description of the systemic characterisation of mixture sample.

A practical application of wavelet moment method on the quantitative analysis of Shuanghuanglian oral liquid based on three-dimensional fingerprint spectra

The overlapping and shifts of peaks and noise signals appear mostly in high performance liquid chromatography (HPLC) experiments. A practical application of wavelet moment method on the quantitative analysis of the main active components in Shuanghuanglian oral liquid samples was presented based on the determination of HPLC coupled with photodiode array detector (PAD). The wavelet moments were calculated from the divided regions in the grayscale images of three-dimensional (3D) HPLC-PAD fingerprint spectra according to the target peak(s), and then used to establish linear models, respectively. The correlation coefficients (R) were more than 0.9980 within the test ranges. The intra- and inter-day variations were less than 1.13% and 1.10%, respectively. The recovery ranged from 96.2% to 102.7%. The overall LODs and LOQs were less than 0.2 μg/mL and 0.7 μg/mL, respectively. Our study indicated that wavelet moment approach could defuse the overlapping and shifts of peaks and noise signals in the chromatographic determination owing to its multi-resolution and inherently invariance properties. Thus the analytical time was shortened, and the obtained results were reliable and accurate.

An efficient approach to the quantitative analysis of humic acid in water.

Rayleigh and Raman scatterings inevitably appear in fluorescence measurements, which make the quantitative analysis more difficult, especially in the overlap of target signals and scattering signals. Based on the grayscale images of three-dimensional fluorescence spectra, the linear model with two selected Zernike moments was established for the determination of humic acid, and applied to the quantitative analysis of the real sample taken from the Yellow River. The correlation coefficient (R(2)) and leave-one-out cross validation correlation coefficient (R(2)cv) were up to 0.9994 and 0.9987, respectively. The average recoveries were reached 96.28%. Compared with N-way partial least square and alternating trilinear decomposition methods, our approach was immune from the scattering and noise signals owing to its powerful multi-resolution characteristic and the obtained results were more reliable and accurate, which could be applied in food analyses.

An approach to the simultaneous quantitative analysis of metabolites in table wines by 1H NMR self-constructed three-dimensional spectra

Wine consists of several hundred components with different concentrations, including water, ethanol, glycerol, organic acids and sugars. Accurate quantification of target compounds in such complex samples is a difficult task based on conventional (1)H NMR spectra due to some challenges. In this paper, the three-dimensional spectrum was constructed firstly by simply repeating (1)H NMR spectrum itself so as to extract the features of target compounds by Tchebichef moment method. A proof-of-concept model system, the determination of five metabolites in wines was utilized to evaluate the performance of the proposed strategy. The results indicate that the proposed approach can provide accurate and reliable concentration predictions, probably the best results ever achieved using PLS and interval-PLS methods. Our novel strategy has not only good performance but also does not require laborious multi-step and subjective pretreatments. Therefore, it is expected that the proposed method could extend the application of conventional (1)H NMR.

Krawtchouk image moment method for the simultaneous determination of three drugs in human plasma based on fluorescence three-dimensional spectra

The interference signals and overlapped peaks are common phenomena in fluorescence determination, which seriously influence the accuracy and reliability of analytical results. In this paper, Krawtchouk image moment method was introduced to the analysis of fluorescence three-dimensional (3D) spectra and applied to the quantitative analysis of three drugs including nicotinic acid, metoprolol and amlodipine in human plasma. Without any pretreatment to the obtained spectra, Krawtchouk moments were directly calculated on the grayscale images of 3D spectra, and the quantitative linear models for the three drugs were established by stepwise regression, respectively. The determination coefficients (R) were more than 0.9906. The correlation coefficients of leave-one-out cross-validation (Rcv) were more than 0.9256. The precisions (RSD, %) of inter-day and intra-day variations were less than 8.4% and 3.1%, separately. The recovery was from 101.84% to 107.88%. The limit of quantification and the limit of detection were 0.12μgmL-1 and 0.43μgmL-1, respectively. All the statistical parameters supported that the obtained models performed well and the proposed method was accurate and reliable. Our study indicates that Krawtchouk image moments with the powerful abilities of multi-resolution and extracting local information can be applied to the simultaneous determination of multi-target compounds in plasma based on fluorescence 3D spectra.

Fast determination of four active compounds in Sanqi Panax Notoginseng Injection samples by high‐performance liquid chromatography with a chemometric method

The application of chemometric methods could decrease the requirements of separation and simplify time-consuming pretreatment and experimental optimization. In this report, the accumulated projection method was developed and utilized for the rapid simultaneous quantification of four active components (notoginsenoside R1, ginsenosides Rg1, ginsenosides Re, and ginsenosides Rb1) in Sanqi Panax Notoginseng Injection samples. The proposed method is based on the three-dimensional fingerprint spectra obtained from high-performance liquid chromatography coupled with photodiode array detection. Although the chromatograms consisted of overlapping peaks, retention time shifts, and unknown interference, all established models showed good linearity (R > 0.9869) within test ranges. The relative standard deviation for intra- and interday precision of the four compounds did not exceed 2.4 and 4.7%, respectively, and the overall recovery was 91.2-106.8%. Compared with N-way principal component analysis, our method provides more satisfactory results, which indicate that the proposed approach is simple, fast, and reliable for the determination of the four analytes in Sanqi Panax Notoginseng Injection samples.

A combined high-performance liquid chromatography with photodiode array detection and chemometric method for the rapid quantitative analysis of multiple components in the traditional Chinese medicine Shuanghuanglian oral liquid

Shuanghuanlian oral liquid, a traditional Chinese medicine preparation, is a mixture of three herbs (Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae). In this study, the quantitative analysis of three main active compounds, chlorogenic acid, forsythin and baicalin in samples from different manufacturers was performed rapidly by high-performance liquid chromatography coupled with photodiode array detection followed by Contour Projection coupled to stepwise regression treatment of the obtained three-dimensional spectra in which the partial overlap between adjacent target components existed. The method was validated for linearity (R>0.9940), precision (RSD<1.25%), recovery (92.20-102.50%), limit of detection (0.01-0.02 μg/mL) and limit of quantification (0.03-0.07 μg/mL). The results indicated that the combination of the three-dimensional spectra of traditional Chinese medicine and Contour Projection-stepwise regression offered an accurate, simple, low-cost and eco-friendly way for the rapid quantitative analysis of Shuanghuanlian oral liquid samples.

High‐performance liquid chromatography with photodiode array detection and chemometrics method for the analysis of multiple components in the traditional Chinese medicine Shuanghuanglian oral liquid

Shuanghuanlian oral liquid, a traditional Chinese medicine preparation, is a mixture of three herbs (Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae). In this study, the quantitative analysis of three main active compounds, chlorogenic acid, forsythin and baicalin in samples from different manufacturers was performed rapidly by high-performance liquid chromatography coupled with photodiode array detection followed by Contour Projection coupled to stepwise regression treatment of the obtained three-dimensional spectra in which the partial overlap between adjacent target components existed. The method was validated for linearity (R>0.9940), precision (RSD<1.25%), recovery (92.20-102.50%), limit of detection (0.01-0.02 μg/mL) and limit of quantification (0.03-0.07 μg/mL). The results indicated that the combination of the three-dimensional spectra of traditional Chinese medicine and Contour Projection-stepwise regression offered an accurate, simple, low-cost and eco-friendly way for the rapid quantitative analysis of Shuanghuanlian oral liquid samples.

Quantitative analysis of multiple components based on liquid chromatography with mass spectrometry in full scan mode

Although liquid chromatography with mass spectrometry in full scan mode can obtain all the signals simultaneously in a large range and low cost, it is rarely used in quantitative analysis due to several problems such as chromatographic drifts and peak overlap. In this paper, we propose a Tchebichef moment method for the simultaneous quantitative analysis of three active compounds in Qingrejiedu oral liquid based on three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry. After the Tchebichef moments were calculated directly from the spectra, the quantitative linear models for three active compounds were established by stepwise regression. All the correlation coefficients were more than 0.9978. The limits of detection and limits of quantitation were less than 0.11 and 0.49 μg/mL, respectively. The intra- and interday precisions were less than 6.54 and 9.47%, while the recovery ranged from 102.56 to 112.15%. Owing to the advantages of multi-resolution and inherent invariance properties, Tchebichef moments could provide favorable results even in the situation of peaks shifting and overlapping, unknown interferences and noise signals, so it could be applied to the analysis of three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry.

An effective approach to quantitative analysis of ternary amino acids in foxtail millet substrate based on Terahertz Spectroscopy

Terahertz time-domain spectroscopy has been applied to many fields, however, it still encounters drawbacks in multicomponent mixtures analysis due to serious spectral overlapping. Here, an effective approach to quantitative analysis was proposed, and applied on the determination of the ternary amino acids in foxtail millet substrate. Utilizing three parameters derived from the THz-TDS, the images were constructed and the Tchebichef image moments were used to extract the information of target components. Then the quantitative models were obtained by stepwise regression. The correlation coefficients of leave-one-out cross-validation (Rloo-cv2) were more than 0.9595. As for external test set, the predictive correlation coefficients (Rp2) were more than 0.8026 and the root mean square error of prediction (RMSEp) were less than 1.2601. Compared with the traditional methods (PLS and N-PLS methods), our approach is more accurate, robust and reliable, and can be a potential excellent approach to quantify multicomponent with THz-TDS spectroscopy.