Prediction of liquid chromatography retention factors for α-branched phenylsulfonyl acetates using quantum chemical descriptors

The logarithms of retention factors normalized to a hypothetical pure water eluent(log k w) were determined on a reversed phase high performance liquid chromatography(RP HPLC) column (Li Chrosorb RP 18 column) for 20 new α\|branched phenylsulfonyl acetates. The atomic charge method was applied to develop quantitative structure retention relationships(QSRRs). Among the available geometric and electronic descriptors, surface area (S), ovality (O), and the charge of carboxyl group(Q OC ) are significant. In the model, the contribution of surface area (S) is the greatest. The molecular mechanism of retention was demonstrated through the model. With the correlation coefficient ( r 2 adj , adjusted for degrees of freedom) of 0.964, the standard error of 0.164 and the F value of 170.39, the model has good predictive capacity.

Predicting Chromatographic Retention Time of C10-Chlorinated Paraffins in Gas Chromatography-Mass Spectrometry Using Quantitative Structure Retention Relationship

Chlorinated paraffins（CPs） are potential persistent organic pollutants（POPs）, which threat the safety of environment and organisms. However, the analysis of CPs is a difficult task due to their complex composition containing thousands of congeners. In the present work, quantitative structure retention relationship（QSRR） of CPs was studied. A total of 470 molecular descriptors were generated, for describing the structures of 28 CPs and 12 descriptors relevant to retention time of the CPs were selected by stepwise regression. Then, QSRR models between retention time on the one hand and the selected descriptors on the other hand were established by multiple linear regres- sion（MLR）, partial least squares（PLS） and least square support vector regression（LS-SVR）. The result shows that PLS model is better than MLR and LS-SVR, obtaining a squared correlation coefficient（r2） of 0.9996 and a root mean squared error（RMSE） of 0.015. The PLS model was then used to predict the retention time of 49 C10-CPs. Three of them were investigated by gas chromatography coupled with mass spectrometry（GC-MS）. A well-defined correlation was found between the measured retention time and the predicted value.

Fluorescence Retention of Organosilane-polymerized Carbon Dots Inverse Opals in CuCl Suspension

A novel and fluorescence retention inverse opal has been achieved from organosilane-polymerized carbon dots（SiCDs）, which is prepared via infiltrating SiCD solution into the interstice of photonic crystal（PC） template, low temperature treatment, heating polymerization and removing the colloidal template. The as-prepared SiCD inverse opals demonstrate close-cell structure, which is completely different from conventional open-cell structure. Then the fluorescence signal of as-prepared sample keeps almost unchanged in CuCl suspension while the fluorescence of SiCD solution can be quenched by CuCl suspension through an effective electron transfer process. This phenomenon can be attributed to the combined effect of high hydrostatic pressure in the pore structure, stable crosslinking network and fluorescence enhancement by PC structure. The SiCD inverse opals have advantages of unique close-cell structure, easy preparation and good repeatability that give an important insight into the design and manufacture of novel and advanced optical devices.