Application Research Of Multivariate/multidimensional Calibration-assisted Accurate Quantification Of Semi-selective Probes/signal

Selectivity is one of the prerequisites for accurate quantitative analysis of target analytes.However,only a few analytical processes are specific.Therefore,appropriate methods are needed to improve the selectivity of the target analyte.At present,it is one of the research hotspots to introduce appropriate chemometric models into the field of instrumental analysis to enhance the selectivity of target analytes and achieve accurate quantitative analysis of target analytes.This thesis focuses on the problem of insufficient selectivity of fluorescence spectroscopy,Raman spectroscopy and HPLC-DAD detection signals in three analytical systems.The selectivity of semi-selective probe signal/semi-selective instrument signal was enhanced by multivariate/multiway calibration methods to achieve accurate quantitative analysis of target analytes in complex systems with interference coexistence.The main research contents of this thesis are as follows:1.Probes such as carbon dots have extensive and important applications in the quantitative analysis of complex biological and environmental systems.However,the development of probes is often hindered by incomplete selectivity,i.e.,a probe that responds to one substance is also prone to respond to coexisting structurally similar substances.Therefore,the above dilemma often leads to be developed as semi-selective probes,so that the development of probes is abandoned halfway.This work shows how a semi-selective probe can enhance selectivity by combining a proper multivariate calibration model.Primarily,we developed a semi-selective fluorescent probe that responded to TCs with discarded tobacco leaves.Then,we introduced the multivariate fluorescence quantitative model to enhance its selectivity and solve the problem of fluorescence spectral shift.For the determination of chlortetracycline with this semi-selective probe CDs-T in mineral and lake water samples,compared to the traditional quantitative model,the introduced QFM model resulted in the ARPE in mineral water spiked samples decreased from 57.1%to 5.6%,which reduced the ARPE in the lake water spiked samples from 18.1%to 4.7%.The above results show that the QFM-assisted semi-selective probe CDs-T strategy(QFM_CDs-T)can enhance selectivity,and QFM_CDs-T achieved high-selective and accurate determination of CTC in interfering mineral and lake water samples,with the LOD and LOQ of 0.55μM and 1.66μM,respectively.The proposed strategy of enhancing selectivity by introducing a proper multivariate calibration model can reduce the difficulty and increase success rate of developing probes,which can be expected to provide an interesting alternative for the development of probes,especially when encountering semi-selective problems.2.Aptamers as probes for specific molecular recognition have important applications in chemical biosensors.However,in complex analytical systems,interferences with similar structures to the target analyte still pose a certain challenge to the quantitative application of aptamers,introducing additional errors.The introduction of multivariate calibration models to assist in enhancing selectivity is a strategy worth studying to improve the accuracy of quantitative analysis.In this chapter,we used the semi-selective probe（Ap-TC）reported in the literature as a probe,based on SERS technology,introduced PLS algorithm,and established a multivariate calibration method for the determination of TC in tablets and aquaculture wastewater samples（cattle wastewater and pig wastewater）.Firstly,we used silver nanoparticles（Ag@ICNPs）combined with Ap-TC to construct a SERS sensor to measure the Raman spectra of the training set and the prediction set（OTC coexisting tablets,cattle wastewater and pig wastewater samples）.Then,we introduce the PLS algorithm to construct a multivariate calibration model,in which the performance of MSC,SNV,and second derivative in dealing with baseline drift and scattering effects is compared and analyzed.The performance of CARS,UVE,and GA in feature variable extraction is compared and analyzed.The results show that MSC-CARS-PLS is the optimal model and can effectively overcome the interference and enhance the selectivity of SERS sensor for quantitative analysis of TC.For the tablet system,the proposed method was used to predict the TC in the spiked validation samples,and the average recovery was101.2%.ARPE was 8.8%;the TC in the real sample of the tablet was predicted,and the predicted results were compared with the real content by t test.The t test showed that there was no significant difference between the predicted results and the real content（At 5%significance）.The inter-day precision of this method was 2.6%.For cattle wastewater and pig wastewater systems,the average recoveries were 97.4%and104.0%,and the ARPE were 7.8%and 6.6%,respectively.The above results show that multivariate calibration can enhance the selectivity of semi-selective aptamer and determine TC with high selectivity and accuracy in tablet and aquaculture wastewater systems.The multivariate calibration model introduced in this paper assists semi-selective aptamer to enhance selectivity and achieve accurate quantification.The strategy can reduce the difficulty of developing aptamer probes and increase the success rate.Especially when semi-selective problems are encountered,it is expected to provide a valuable strategy for the accurate quantification of aptamers.3.HPLC method（based on UV-visible spectral detector）has been widely used in complex analytical systems such as chemistry,biology,environment and food due to its excellent separation ability.However,the co-elution problem often occurs in the separation and analysis of multi-analytes in complex systems,that is,there is chromatographic overlap between the analyte and the analyte,the analyte and the interferences.The mathematical separation function of three-way calibration is expected to enhance chromatographic separation（i.e.,enhance the selectivity of chromatographic signals）to solve the co-elution problem.In this work,we developed a three-way calibration-assisted high-performance liquid chromatography-diode array detection（TW-HPLC-DAD）method.It was used for rapid and accurate quantitative analysis of seven deoxynucleotides（d A,d G,d C,d T,d AMP,d GMP,and d TMP）in three complex systems of mineral water,tobacco leaves and cells.In this method,firstly,the analyte was preliminarily and rapidly separated by simple chromatographic separation conditions（incomplete separation of the analyte）.The second-order data of chromatography-ultraviolet-visible spectroscopy were measured one by one for the calibration sample and the prediction sample,and stacked into a three-way data array of chromatography-ultraviolet-visible spectroscopy-sample.Then,from the mixed signals with interference coexistence,the chromatographic,spectral and concentration pure profiles of the analytes were extracted using a trilinear decomposition algorithm（i.e,mathematical separation was introduced to enhance chromatographic separation）,and quantitative results were obtained by linear regression based on the calibration set.In the three complex analytical systems of mineral water,tobacco leaves and PC3 cells,the average recoveries of the seven deoxynucleotides were 95.2-100.1%,82.2-112.6%and 83.1-109.3%,respectively.The LODs were 0.01-9.2μM,and the LOQs were 0.04-27.8μM.We selected the mineral water and PC3 cells system to verify the reproducibility of the proposed analytical method.The RSDs of the seven deoxynucleotides in the two systems were between 0.4-3.1%and 2.2-10.9%,respectively.The TW-HPLC-DAD analysis method proposed in this work enhances the selectivity of chromatographic separation by three-way calibration,which effectively reduces the difficulty of developing chromatographic separation conditions,reduces the use of organic solvents and saves the time of separation and analysis（single sample separation time is reduced from 18 minutes of complete chromatographic separation to less than 6 minutes）.It is worth mentioning that the calibration set of this method can predict the above prediction samples containing multiple interferences only by preparing in pure solution,which has good versatility and does not need to update and transfer the model.The above results show that the TW-HPLC-DAD analysis method proposed in this paper can provide a rapid and accurate chromatographic separation quantitative strategy for the quantitative analysis of multiple analytes in various complex systems.In this paper,fluorescence spectroscopy,Raman spectroscopy and HPLC-DAD are used as the research objects.The selectivity of semi-selective probe（CDs-T and Ap-TC）/semi-selective instrument signal（HPLC-DAD）is enhanced by multivariate/multi-way calibration methods（QFM,PLS and three-way calibration）,respectively.The accurate quantitative analysis of different target analytes in the complex system of mineral water,lake water,tetracycline tablets,pig wastewater,cattle wastewater and PC3 cell samples under interference coexistence was carried out.