Thin-Layer Chromatographic Separation of Amino Acid Enantiomers using Ligand Exchange

Silica gel thin-layer plates covered with L-arginine and copper acetate were used for the separation of amino acid enantiomers, The chromatographic selectivity and the effects of plate different preparation methods, sample molecular structure and solvent compositions on resolution performance were also discussed.

ANALYSIS OF STRYCHNINE ALKALOIDS IN BIOLOGICAL SAMPLES BY THIN-LAYER CHROMATOGRAPHIC DENSITOMETRY AND DISTRIBUTION STUDY OF STRYCHNINE IN INTOXICATED RATS

A sensitive and rapid analytical procedure was established to detrmine strychnie alkaloids in diverse biological specimens. Samples were treated with hydrochloric acid to precipitate protein and scanned in thin-layer chromatograpic scanner in zig-zag dual-wavelength reflection mode.Detection sensitivity for strychniue was about 0. 05 μg. Quantification recoveries were between89. 2% and 99. 5% with RSD between 2. 92% and 13. 21 %. The method was applied to investigate thedistribution or strychnine in intoxicated rats. The results showed that there were remarkable difference in organs or tissues with the aigaest concentration 4. 56±1. 41μg/g in liver. Diversification experiment proves the method also could be used to analyze other alkaloids in biological samples if theconditions slightly modified.

Characteristics and main controlling factors of intra-platform shoal thin-layer dolomite reservoirs:A case study of Middle Permian Qixia Formation in Gaoshiti-Moxi area of Sichuan Basin,SW China

Based on the study of the distribution of intra-platform shoals and the characteristics of dolomite reservoirs in the Middle Permian Qixia Formation in the Gaoshiti–Moxi area of the Sichuan Basin,SW China,the controlling factors of reservoir development were analyzed,and the formation model of“intra-platform shoal thin-layer dolomite reservoir”was established.The Qixia Formation is a regressive cycle from bottom to top,in which the first member(Qi1 Member)develops low-energy open sea microfacies,and the second member(Qi2 Member)evolves into intra-platform shoal and inter-shoal sea with decreases in sea level.The intra-platform shoal is mainly distributed near the top of two secondary shallowing cycles of the Qi2 Member.The most important reservoir rock of the Qixia Formation is thin-layer fractured-vuggy dolomite,followed by vuggy dolomite.The semi-filled saddle dolomite is common in fracture-vug,and intercrystalline pores and residual dissolution pores combined with fractures to form the effective pore-fracture network.Based on the coupling analysis of sedimentary and diagenesis characteristics,the reservoir formation model of“pre-depositional micro-paleogeomorphology controlling shoal,sedimentary shoal controlling dolomite,penecontemporaneous dolomite benefiting preservation of pores,and late hydrothermal action effectively improving reservoir quality”was systematically established.The“first-order high zone”micro-paleogeomorphology before the deposition of the Qixia Formation controlled the development of large area of intra-platform shoals in Gaoshiti area during the deposition of the Qi2 Member.Shoal facies is the basic condition of early dolomitization,and the distribution range of intra-platform shoal and dolomite reservoir is highly consistent.The grain limestone of shoal facies is transformed by two stages of dolomitization.The penecontemporaneous dolomitization is conducive to the preservation of primary pores and secondary dissolved pores.The burial hydrothermal fluid enters the early dolomite body along the fractures associated with the Emeishan basalt event,makes it recrystallized into medium–coarse crystal dolomite.With the intercrystalline pores and the residual vugs after the hydrothermal dissolution along the fractures,the high-quality intra-platform shoal-type thin-layer dolomite reservoirs are formed.The establishment of this reservoir formation model can provide important theoretical support for the sustainable development of Permian gas reservoirs in the Sichuan Basin.

Photothermal-photocatalytic thin-layer flow system for synergistic treatment of wastewater

The integration of the photocatalytic effect into solar steam is highly desirable for addressing freshwater shortages and water pollution.Here,a ternary film structure for the adsorption and photothermal and photocatalytic treatment of wastewater was designed by combining the technique of self-assembled carbon nano paper with a nitrogen composite titanium dioxide(N-TiO_(2))deposited on the surface of carbon nanotubes(CNT)using polyvinylidene fluoride(PVDF)as a substrate.The photogeneration of reactive oxygen species can be promoted by rapid oxygen diffusion at the three-phase interface,whereas the interfacial photothermal effect promotes subsequent free radical reactions for the degradation of rhodamine B(93%).The freshwater evaporation rate is 1.35 kg·m^(-2)·h^(-1)and the solar-to-water evaporation efficiency is 94%.Importantly,the N-TiO_(2)/CNT/PVDF(N-TCP)film not only effectively resists mechanical damage from the environment and maintains structural integrity,but can also be made into a large film for outdoor experiments in a large solar energy conversion device to collect fresh water from polluted water and degrade organic dyes in source water simultaneously,opening the way for applications in energy conversion and storage.

Simple and Rapid Thin-layer Chromatography Method for Quantitative Measurement of Free Cholesterol in Serum

ABSTRACT A quantitative method for the assay of free cholesterol has been described in this paper. The experimental conditions for the determination of cholesterol in serum by Thin-layer chromatography were disscused. The solvent System was petroleum ether-ethyl acetate-glacial acetic acid (8o:20:1) and the spra-ying reagent was a solution of sulphuric acid and vanillin. Under the selected con-ditions, the peak area was linearly related to the cholesterol amount for the range between 80～700 ng per spot. The intraplate and interplate coefficients were 2.4% and 7.4% respectively. The recovery of cholesterol was 101.6%. The method presented was simple, rapid and accurate. The results of experi-mental investigation and clinical application were satisfactory.

Quality Evaluation of Leontopodium franchetii Beauv. from Different Localities Based on Moisture,Ash and Extract Contents and Thin-layer Chromatography

[Objectives] The aim was to determine the moisture,ash and extract contents in Leontopodium franchetii Beauv. from different localities. [Methods] The contents of moisture,total ash,acid-insoluble ash and extract in L. franchetii from different localities were determined according to the methods described in Chinese Pharmacopoeia( 2015 Edition). [Results] In the 10 samples,the contents of moisture were all less than or equal to 15. 0%; the contents of total ash were all below 12. 0%; and the contents of acid-insoluble ash were all less than 3. 0%. The contents of water-soluble extract( by cold-soaked extraction method) in the samples were all below 12. 0% except those from Hongyuan Prairie of Sichuan Province and Xinglong Mountain in Lanzhou City,Gansu Province. [Conclusions]The contents of the four indicators measured in this experiment varied by small margins,indicating that the quality was relatively stable. This study provides theoretical data for the revision of the quality standards for L. franchetii.

Separation of Amino Acids Based on Thin-Layer Chromatography by a Novel Quinazoline Based Anti-Microbial Agent

A newly designed quinazoline based compound, 6-pyridin-2-yl-5,6-dihydro-benzo[4,5]imidazo[1,2-c] quinazoline (PDBIQ) has shown the ability for the easy detection of nineteen amino acids on thin-layer chromatography plates as a spray reagent. This new reagent enabled to produce various distinguishable colors with amino acids with different RF values. The detection limits and the binding ability of PDBIQ with amino acids have been calculated. PDBIQ is also able to detect aminoacids from hydrolised seed protein. The title compound also exhibited profound inhibitory action against some gm (+ve) and gm (-ve) bacterial organisms. This paper deals with synthesis, spectroscopic application and biological evaluation of the organic moity.

ANALYSIS OF HUMAN PLACENTA BY ^(31)P NUCLEAR MAGNETIC RESONANCE AND THIN-LAYER CHROMATOGRAPHY SCANNING COMBINED WITH THE CORRECTIVE METHOD OF ABSORBANCE PROPORTIONAL COEFFICIENT

Five phospholipids in human placenta were determined by phosphorus 31 nuclear magnetic resonance(^(31)P NMR)spectroscopy and thin-layer chromatography(TLC) scanning combined with the corrective method of absorbance proportional coefficient. The NMR spectrometer used this investigation was a Bruker AM-500 spectrometer operating at 202.4 MHz for ^(31)P chemical shifts are relative to 85% phosphoric acid. TIC was carried out by silica gel H plate developed in chloroform-methanol-glacial acetic acid-ethanol-water(25:4:6:2:0.5),with Vaskovsky reagent as colour -developing agent of phospholipids.

A QSRR Study on the Chromatographic Retention Indices of Hydroxylated Polychlorinated Biphenyls

Hydroxylated Polychlorinated Biphenyls （HO-PCBs） are the metabolite of polychlorinated biphenyls and have drawn much attention because they have hazard on human health and ecosystems. Molecular connectivity index calculation has been performed for 19 HO-PCB compounds. A number of statistically based parameters have been extracted. Linear relationship between chromatographic retention index （RI） and the molecular connectivity index of 15 compounds in the training set has been established by multiple linear regression method. The other 4 HO-PCBs are used as the external test set. The result shows that the parameters can be well used to express the quantitative structure-retention relationship （QSRR） of HO-PCBs. Good stability and predictive ability have been demonstrated by leave-one-out cross-validation and the external test set.

Quantitative Correlation of Chromatographic Retention and Acute Toxicity for Alkyl(1-phenylsulfonyl) Cycloalkane Carboxylates and Their Structural Parameters by DFT

Twenty eight alkyl(1-phenylsulfonyl) cycloalkane carboxylates were computed at the B3LYP/6-31G* level. Based on linear solvation energy theory, two quantitative correlation equations of the molecular structures of alkyl(1-phenylsulfonyl) cycloalkane carboxylate com- pounds to their chromatographic retention (capacity factor lgKW) and the toxicity for photo- bacterium phosphoreum (–lgEC50) were developed by using the molecular structural parameters as theoretical descriptors (r2 = 0.9501, 0.9488). The two quantitative correlation equations were consequently cross validated by leave-one-out (LOO) validation method with q2 of 0.9113 and 0.9281, respectively. The result showed that the two equations achieved in this work by B3LYP/6-31G* are both more advantageous than those from AM1, and can be used to predict the lgKW and –lgEC50 of congeneric organics.

Development of chromatographic technologies for the quality control of Traditional Chinese Medicine in the Chinese Pharmacopoeia

As an important branch of medicine, Traditional Chinese Medicine(TCM) has been applied for the treatment of diseases for thousands of years in China and other countries in East Asia. The Chinese Pharmacopoeia(ChP) is a drug code formulated by the Chinese government, and it includes a special volume for the monographs of TCM, which plays an important role in ensuring the quality of drugs. The use of quality control technology has always been a complex and important factor in TCM. Owing to the chemical diversity of TCM, chromatography technology has been proven to be a comprehensive strategy for the assessment of the overall quality of TCM and has become the main analytical method in the ChP.This article provides an overview of the classical and modern chromatographic technologies applied in the ChP, and summarizes the advantages and disadvantages of each technique in the TCM monographs.In 2020, the new edition of the Ch P(the 2020 edition) has been implemented at the end of 2020. This paper also contains a brief introduction about the application of chromatographic technologies in the new edition of the ChP.

Quality evaluation of Huaijiao pill by chromatographic fingerprint and simultaneous determination of its major bioactive components

For quality control purpose,an approach of combining chromatographic fingerprint of Huaijiao pill（HP）and simultaneous determination of its major bioactive components was developed using high performance liquid chromatography coupled with diode array detector（HPLC-DAD）.For fingerprint analysis,16 peaks were selected as the characteristic peaks to evaluate the similarities of different samples collected from different batches of three manufacturers.The similarities of 17 Huaijiao pill samples were beyond 0.966,indicating that samples from different batches and manufacturers were,to some extent,consistent.Additionally,simultaneous quantification of seven bioactive markers,namely sophoricoside,baicalin,naringin,genistein,rutin,quercetin and 5-O-methylvisammioside,in HP was performed to interpret the quality consistency.The validation of the proposed approach was acceptable,with the accuracy of 90.2%-106.9%in recovery test.The intra-day and inter-day precisions of the method were evaluated and the RSD values were less than 2.81%.The results from the quantitative data showed that the contents of six marker compounds（except for 5-O-methylvisammioside） were quite consistent between batches produced by one manufacturer and significantly distinctive among different manufacturers.The proposed approach was expected to be developed as a powerful tool for the quality control of HP.

Study on chromatographic fingerprint of sarcandra glabra (Thunb.) by microwave-assisted extraction coupled to HPLC/DAD

Microwave-assisted extraction(MAE)was used for extraction of effective components of sarcandra glabra(Thunb.),and then chromatographic fingerprint of sarcandra glabra(Thunb.)was studied by high performance liquid chromatography/diode array detector(HPLC/DAD).The conditions of MAE were optimized by an orthogonal experiment,and then the authentication and validation of the chromatographic fingerprint were conducted.Nine peaks were identified as common peaks in the fingerprint chromatograms,and isofraxidin was considered as a reference compound and quantified.Relative standard deviations of retention time and peak area of each component were less than 3% and 8%,respectively.Similarity and difference analysis were conducted by use of PCA and relation coefficient.Twenty batches of sarcandra glabra(Thunb.)samples from two different producing areas could be classified into two different groups in the PCA model.The results showed that MAE-HPLC/DAD method was simple,efficient and stable for the study of complex chromatographic fingerprint of sarcandra glabra(Thunb.),which could provide more reliable and precise information for quality evaluation.

Evaluation of reservoir connectivity using whole-oil gas chromatographic fingerprint technology: A case study from the Es_3~3 reservoir in the Nanpu Sag, China

In this study, whole-oil gas chromatographic fingerprint analyses were performed on oils from the Es3^3 reservoir in the Liubei area of the Nanpu Sag. The gas chromatographic peaks of cyclic and branched alkanes with relatively high resolution from nCl0 to nC25 were selected to establish a database of whole-oil gas chromatographic peak height ratio fingerprints. Reservoir fluid connectivity was identified by using clustering analysis. This method can reflect the gas chromatography fingerprint information accurately and entirely, and avoid the one-sidedness of the star diagram method which only selects several fixed gas chromatographic peaks.

Application of a Quartz Crystal Microbalance (QCM) System Coated with Chromatographic Adsorbents for the Detection of Olive Oil Volatile Compounds

A sensor based on the technique of a piezoelectric quartz crystal microbalance (QCM) is analyzed for the detection of six organic volatile compounds with high olive oil sensory significance, such as hexanal, acetic acid, Z-3-hexenyl acetate, undecane, 1-octen-3-ol and 2-butanone. Four sample concentrations have been exposed to each QCM sensor constructed. The detection system is based on the sample adsorption on the forty sensing films coated at the surfaces of forty AT-cut gold-coated quartz crystals. Each sensing film has been prepared with different solution concentrations of ten materials, usually used as chromatographic sta-tionary phases. Sensing film coating process shows excellent repeatability, with coefficient values less than 0.50%. The frequency shifts of the piezoelectric crystals due to the adsorption of the volatile compounds have been measured as sensor responses, using a static measurement system. The results show that only five QCM sensors, with high sensitivity values, are enough to the detection of the volatile compounds studied. Therefore, the developed detection system presented herein provides a rapid identification of organic volatile compounds with elevated olive oil sensory connotation and it could be a substitute technique to the analytical methods normally used for the analysis of the olive oil flavor.

A review of SAGD technology development and its possible application potential on thin-layer super-heavy oil reservoirs

Super-heavy oil is a significant unconventional energy source,and more than 30 years of research have shown that steam-assisted gravity drainage(SAGD)technology is suitable for thick super-heavy oil reservoirs.Recently,more and more thin-layer super-heavy oil reservoirs have been discovered in China,while their deep buried depth and serous heterogeneity make the existing SAGD technology difficult to apply,so it is urgent to improve the existing SAGD technology for the thin-layer super-heavy oil.To this end,this paper focuses on the enlightenment of field application in SAGD technology.Firstly,based on typical SAGD field projects,the development history of SAGD technology in the world was reviewed,and the influence of reservoir physical properties on the application of SAGD technology in thin-layer superheavy oil reservoirs was analyzed.Secondly,the well pattern,wellbore structure,pre-heating,artificial lift,and monitor technique of SAGD were detailed described,and their adjustment direction was expounded for the development of thin-layer super-heavy oil reservoirs.Lastly,the gas-and solventassistant SAGD were comprehensively evaluated,and their application potential in thin-layer superheavy oil reservoirs was studied.The research results can provide theoretical guidance for the application of SAGD technology in thin-layer super-heavy oil reservoirs.

APPLICATIONS AND MANUFACTURE OF THE MICROSCALE LONG-OPTICAL-PATH ELECTROCHEMICAL CELL WITH A PLUG-IN THIN-LAYER ELECTRODE

The construction and characteristics of a microscale long-optical-path electrochemi- cal cell with a plug-in thin-layer electrode are described.Using ferricyanide as the test species,the thermodynamic parameters of electron transfer processes are determined at car- bon,plantinum,and gold electrodes.

A Study on Relationship Between Gas Chromatographic Retention Value and Atomic Hydrophobic Parameters

A study on relationship between molecular structure and chromatographic retention values for realizing the identification and prediction of chromatographic retention values has been the major task of chromatographic thermodynamics. In 1964, Prof. Lu Peizhang established the relationship between molecular structural parameters and chromatographic retention values in gas-liquid chromatography by using statistical thermodynamical methods. Based on his work, some Chinese researchers have performed the prediction of chromatographic retention values.

STUDIES ON COUNTERACTING CHROMATOGRAPHIC ELECTROPHORESIS AND ITS UTILIZATION FOR PROTEIN PURIFICATION

A counteracting chromatographic electrophoresis(CACE)separation device has been success-fully built and tested.Experiments are performed with protein mixtures of BSA,Hg,Mg and Cyto-cto study the separation performances,concentration profiles,start-up methodology as well as influ-ences of pH and ionic strength on the separation process.Mathematical models based on the fluiddynamics of the porous medium are proposed.Experiments indicate that the CACE process has agood commercial potential in protein engineering and fine chemicals purification.

Synthesis of Cellulose Tris (4-Methylbenzoate) as Gas Chromatographic Stationary Phase and its Characterization

The cellulose tris (4-methylbenzoate) has been synthesised by the catalytic method and was supported at Gas Chrom Q. The absorption capability of cellulose tris (4-methylbenzoate) used as a gas chromatographic stationary phase was characterized by chromatographic method and the Clausius-Clapeyron equation. However, n-alcohols (C-1-C-8) were successfully separated on the column packed with Gas Chrom Q coated with cellullose tris (4-methylbenzoate).