Study On The QSRR/QRTR Models And The Selectivity,Separation Mechanism Of Stationary Phase Based On RP-HPLC

High performance liquid chromatography(HPLC)is a model of a large,mature,simple operation,wide application of separation and analysis with the high separation efficiency and stability so that which in line with the requirements for the separation and analysis of life substances and pharmaceutical substances from hot spots.So,HPLC is always one of the hot spots in analytical chemistry,and the research on its retention and separation mechanism is more and more deeply.In spite of the new separation mode constantly emerging,RP-HPLC is still the most basic and effective method of separation.In this mode,the retention behavior of the materials is mainly determined by the hydrophobic interaction between the materials and the stationary phase.Therefore,the study of the relationship between the retention behavior of the substance and its hydrophobic belongs to the research scope of the RP-HPLC basic theory.This paper was established a linear relationship between the apparent n-octanol/water partition coefficient and the RP-HPLC retention behavior as the QSRR model by using aromatic compounds as model compounds and the Kow data of compounds with similar structure were predicted by the model.In addition,in this paper the Kow data of two compounds were directly determined by the shake flask method(SFM)combined with HPLC,which was compared with the predictive value of the QSRR model.The established QSRR model is applied in the complex system of toxicity components analysis.A new strategy is put forward in this study:with Kow as a bridge to establish the relationship between the retention behavior(kw)and the toxicity parameters(LO2 cytotoxicity)of the toxic components(QRTR).Finally,based on the retention behavior of compounds,the separation selectivity and thermodynamic separation mechanism of compounds with similar structures on different stationary phases were analyzed.The maincontent reads as follows:1.Establishment and verification of QSRR model.In this paper,a set of 28 neutral and acidic analogues of naphthalene and anthraquinone with reliable experimental Kow data was chosen as model compounds for establishing linear relationship between the logarithm of apparent n-octanol/water partition coefficient(logKow"),and the logarithm of RP-HPLC retention factor of the solutes corresponding to the neat aqueous fraction of mobile phase(logkw)as the QSRR model.Methanol-water mixture was used as mobile phase at various mobile phase pH,and retention time(tR)was rectified by a dual-point retention time correction(DP-RTC)in this method.The result indicated the proposed QSRR model had good correlation coefficient R2=0.974?0.976 with satisfactory results of internal and external validation(the cross-validated correlation coefficient R2cv of 0.970-0.973,and 1.4%?relative error(RE)?7.9%for all the 6 verification compounds).In addition,this QSRR model was compared with linear solvation energy relationship(LSER)involved in different descriptors of molecular structure,showing results of no differences.The proposed strategy provides the possibility in determining Kow of lipophilic components in complex mixture more quickly and accurately by RP-HPLC.2.Application of QSRR model in prediction of Kow valueThe QSRR model was applied to measure logKow of 12 naphthalenes and anthraquinones,and the predicted data were compared with experimental SFM ones,as well as calculated ones obtained by ACD/Lab software.The result suggested that the proposed method for Kow determination in this work is more accurate,simple and fast with the relative error(RE)at 1.8%and 2.4%,while the the error between the calculated value and the predicted value of the QSRR model is obviously larger with the 0.2%?RE?43.4%.To the best of our knowledge,this is the first report on measured Kow data for these compounds3.Construction of QRTR modelLO2 cell toxicity test was carried out on 28 model group compounds of QSRR model in the early stage by using lactate dehydrogenase(LDH)kit,the result suggested that there are 10 model compounds have cytotoxicity on LO2 cells at 20?M,100?M and 500?M.In this chapter,we established the relationship between the cytotoxicity and logKow which defined as QSTR model and the relationship of QSRR model.Meanwhile,with Kow as a bridge to establish the relationship between the retention behavior(kw)and the toxicity parameters(LO2 cytotoxicity)of the toxic components(QRTR).The results show that the fitted QSRR,QSTR and QRTR models have good linearity with R2=0.891?0.9754.Effect of column temperature on separation selectivity and the mechanism of different stationary phasesBased on the retention behavior of compounds,the separation selectivity and thermodynamic separation mechanism of compounds with similar structures on different stationary phases and the effect of change in column temperature on van't Hoff equation,as well as the relationship between separation efficiency and column temperature on HPLC by using different stationary phases,have been discussed and compared in this paper.In addition,we first put forward a linear relationship between the column phase ratio and temperature with great linear relationship(R2 ? 0.99).Furthermore,a relationship relating selectivity and column temperature was deduced in theory,applied to predict the separation of six steroid hormones on HPLC with high consistency between experimental and predicted selectivity factors(average relative errors wrer 0.0%?2.2%for C18 column,0.0%?1.0%for cholesterol column,0.0%?6.1%for C8 column and 0.0%?5.1%for ODP column,respectively),which show that the method can effectively predict the resolution of the estrogen in the experimental temperature range.