The role of planar chromatography in medicinal plant research

This paper summarizes the role of planar chromatography (PC) in medicinal and aromatic plant (MAP) research and development, and demonstrates the importance of the technique, after extraction, in the analysis of MAP (identification and quantitative determination of the separated compound/s), in the purification and isolation process, and in different types of screening procedure. Special attention is paid to analytical, micropreparative and preparative forced-flow techniques, for example overpressured-layer chromatography (OPLC) and rotation planar chromatography (RPC). The special features of analytical, micropreparative, and preparative layer chromatography (PLC), OPLC, and RPC are compared in tables. Purification and isolation procedures using forced-flow techniques are shown in flowcharts. Some applications, relating to different classes of substance, are presented to demonstrate the versatility of various planar chromatographic techniques.     

Review of thin-layer chromatography in pesticide analysis: 2014–2016

ABSTRACT

Publications reporting techniques and applications of thin-layer chromatography (planar chromatography) for the separation, detection, qualitative and quantitative determination, and preparative isolation of pesticides and their metabolites are reviewed for the period from November 1, 2014 to November 1, 2016. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue analysis, studies such as pesticide chromatographic retention, identification and characterization of natural pesticides, metabolism, bioactivity, degradation, soil mobility, and lipophilicity are covered. The unique advantages of thin-layer chromatography in presenting results as a stored image on an open stationary phase are addressed.     

Overpressured Thin-Layer Chromatography and Its Applications

Abstract

In recent years, a rapid progress can be observed both in column and planar liquid chromatographic techniques. In the field of liquid column chromatography the most spectaular achievement was the development of high-performance liquid chromatographic/HPLC/ systems by means of several special instruments and sorbents/1, 2/. As regards planar techniques, the most significant break-through is the development of highperformance thin-layer chromatography/HPTLC//3/ based on the application of fine-particle sorbents. Both techniques proved to be very useful in many fields of chemical analysis, although the use of the latter is more restricted, mainly to micro chromatographic studies.     

Planar chromatography at the turn of the century.

An overview of the state-of-the-art of modern thin-layer chromatography (planar chromatography) is presented with emphasis on the complementary features of thin-layer and column liquid chromatographic separations. The reasons for selecting thin-layer chromatography for a particular analysis are identified by its attributes: a disposable stationary phase; simultaneous parallel separations; static detection free of time constraints; storage device for chromatographic information; all sample components are observed in the chromatogram. Future prospects for improved separation performance in TLC using zone refocusing, forced flow and electroosmotic flow methods are discussed as well as increasing zone capacity by using two-dimensional development and coupling to column chromatographic methods. Advances in coupling thin-layer chromatography with spectroscopic methods for structural elucidation are also considered. Finally, some predictions are made for how thin-layer chromatography will be practiced in the future.     

Planar chromatographic method development using the PRISMA optimization system and flow charts

This study presents a modern planar chromatographic method-development procedure, based on the "PRISMA" optimization system, in which the optimum separation is achieved systematically and the structures and properties of the substances to be separated are not known. The procedure consists of three stages. In the first of these the basic conditions the stationary phase, vapor phase, and individual solvents are selected with a TLC procedure (generally in nonsaturated chromatographic chambers). In the second stage, the optimum combination of the selected solvents is determined with the PRISMA model. The third part of the procedure includes the selection of the development mode (circular, linear, or anticircular); the selection of an appropriate forced-flow chromatographic technique (over-pressured layer chromatography or rotation planar chromatography) with high-performance thin-layer chromatographic plates; the transfer of the optimized mobile phase to the various analytical, planar, or column preparative liquid chromatographic techniques; and the selection of the operating conditions. For practical reasons, the optimization process is presented with the help of flow charts.     

Progress in forced-flow planar chromatography

This paper summarizes progress in forced-flow planar chromatography (FFPC) and demonstrates the importance of the different techniques like rotation planar chromatography (RPC), overpressured-layer chromatography (OPLC), and electro-planar chromatography (EPC). Special attention is paid to a novel analytical FFPC method in which continuous development and continuous evaporation of the mobile phase from the end of the chromatographic plate ensure forced-flow development. A simple, but powerful preparative forced-flow technique is also reported; in this technique hydrostatic pressure is used to increase mobile-phase velocity. Parallel- and serially coupled layers open up new vistas for the analysis of a large number of samples (up to 216) for high throughput screening and for the analysis of very complex matrices. The special features of fully off-line and fully on-line RPC, OPLC, and EPC are compared in a table. New detection methods—on-line coupling of OPLC with radiodetection and on-line OPLC–MS—are also discussed. The role of a new spraying device for post-chromatographic chemical detection and for biological detection is also discussed. Some applications, relating to different classes of substances, are given to demonstrate the versatility of the various FFPC techniques.     

Chromatographic and electrophoretic procedures for analyzing plant pigments of pharmacologically interests

The achievements in the use of chromatographic and electrophoretic techniques including thin-layer chromatography, high-performance liquid chromatography and capillary electrophoresis for the separation and quantitative determination of pharmacologically interesting plant pigments in various sample matrices such as medicine, plant, foods and food products, etc. are surveyed and critically evaluated.     

Techniques for gas chromatography of volatile terpenoids from a range of matrices.

The commercial importance of the volatile mono- and sesqui-terpenoids has resulted in a wide range of techiques being used for extraction, concentration, chromatography, and characterisation of constituents. The major chromatographic technique is gas chromatography, and tandem techniques of chromatography linked to further chromatography and spectroscopy, allow much increased resolution, and greater ease of characterisation of terpenes. A wide range of extraction techniques are discussed, and suitability for particular matrices and sample sizes outlined. Chromatography operating conditions and stationary phases, and techniques for solute identification are laid out. A number of applications of terpene analysis in many different matrices are discussed.     

Preparation of samples of plant material for chromatographic analysis

The selection, collection, and preliminary treatment of plant material samples are discussed. Stages of sample preparation and extraction techniques presently used are described, and the most recent examples of sample preparation for chromatographic analysis are reviewed. Recent applications of gas chromatography for the assessment of emission of volatile organic compounds by plants are also described.     

Toxicological screening by liquid chromatography

Toxicological screening commonly requires analysis of biological specimens by a variety of colorimetric, immunological and chromatographic techniques. Gas chromatography and thin-layer chromatography are useful for simultaneous identification of multiple drug classes, but both methods require sample pretreatment. Recently, liquid chromatography has been applied to untreated urine and serum. A series of columns are utilized for sample purification, as well as efficient separation of drugs. Multiple wavelength UV detection provides sufficient data for qualitative identification of drugs and their metabolites.     

Chromatographic determination of lactulose

Summary Lactulose is a disaccharide with important implications in medicine, nutrition and dairy technology. It has to be determined usually as a minor component in complex matrices containing many other sugars. This paper describes the different chromatographic techniques (planar, liquid and gas chromatography) which have been proposed for the separation and quantification of lactulose in mixtures with other carbohydrates; the advantages of each technique are compared and some features where more research is necessary are outlined.     

A Modified Device for Pressurized Planar Electrochromatography and Preliminary Results with On-Line Sample Application

Pressurized planar electrochromatography (PPEC) is a separating technique in which an electric field is applied to force the mobile phase movement through a porous media (electroosmotic effect). High separation efficiency, fast separations and changes in separation selectivity in comparison to liquid chromatography, especially thin layer chromatography (planar chromatography, TLC), are features of this technique. Constructional methodological challenges to PPEC are obstacles to its development and application in laboratory practice. In this article, an attempt to overcome the challenges related to device construction and sample application/injection is described. The introduced device enables both prewetting of the adsorbent layer and electrochromatogram development with a single PPEC device. It also enables simultaneous application/injection of six samples on a chromatographic plate in a stream of the mobile phase (on-line application/injection). In addition, the PPEC chamber was equipped with a thermostat. The device is characterized by an impressive throughput in comparison to the other planar technique, TLC/HPTLC. Although the developed device still needs improvement, it is, in our opinion, a considerable step toward possible automation of this planar separation technique.     

Design of experiment techniques for the optimization of chromatographic analysis conditions: A review

Design of experiment (DoE) techniques have been widely used in the field of chromatographic parameters optimization as a valuable tool. A systematic literature review of the available DoE techniques applied to the development of a chromatographic analysis method is presented in this paper. First, the most common available designs and the implementation steps of DoE are comprehensively introduced. Then the studies in recent 10 years for the application of DoE techniques in various chromatographic techniques are discussed, such as capillary electrophoresis, liquid chromatography, gas chromatography, thin-layer chromatography, and high-speed countercurrent chromatography. Current problems and future outlooks are finally given to provide a certain inspiration of research in the application of DoE techniques to the different chromatographic techniques field. This review contributes to a better understanding of the DoE techniques for the efficient optimization of chromatographic analysis conditions, especially for the analysis of complex systems, such as multicomponent drugs and natural products.     

Biennial review of planar chromatography: 2011–2013

The most important advances in planar chromatography published between November 1, 2011 and November 1, 2013 are reviewed in this paper. Included are an introduction to the current status of the field; student experiments, books, and reviews; theory and fundamental studies; apparatus and techniques for sample preparation and TLC separations (sample application and plate development with the mobile phase); detection and identification of separated zones (chemical and biological detection, TLC/mass spectrometry, and TLC coupled with other spectrometric methods); techniques and instruments for quantitative analysis; preparative layer chromatography; and thin layer radiochromatography. Numerous applications to a great number of compound types and sample matrices are presented in all sections of the review.     

Analysis of turkish lignite tar by coupled LC/GC,GC/MS,and capillary SFC

This work describes the analysis of a pyrolysis product of a lignite sample obtained from the Turkish Goynuk reserve. The aliphatic, aromatic and polar compounds present in the tar are separated and identified by various chromatographic techniques: Capillary gas chromatography/mass spectrometry (GC/MS), on-line high performance microbore liquid chromatography/capillary gas chromatography (LC/GC) and capillary supercritical fluid chromatography (SFC). The suitability of each technique for this particular application is discussed, and semi-quantitative results are presented for the major components detected.     

Biennial review of planar chromatography: 2009-2011

The most important advances in the planar chromatography published between November 1, 2009 and November 1, 2011 are reviewed in this paper. Included are an introduction to the current status of the field; history, student experiments, books, and reviews; theory and fundamental studies; apparatus and techniques for sample preparation and TLC separations (sample application and plate development with the mobile phase); detection and identification of separated zones (chemical and biological detection, TLC/MS, and TLC coupled with other methods); techniques and instruments for quantitative analysis; preparative layer chromatography; and thin layer radiochromatography. Selected applications are given in the various sections of the review, especially for modern HPTLC-densitometry.     

Comprehensive two-dimensional chromatography in food analysis

Comprehensive two-dimensional (2D) chromatographic techniques can be considered innovative methods, only quite recently developed. Since their introduction to the chromatographic community, these techniques have been used in several fields and have gained an excellent reputation as valuable and powerful analytical tools. The revolutionary aspect of comprehensive multidimensional (MD) techniques, in respect to classical MD chromatography, is that the entire sample is subjected to the 2D advantage. The resulting unprecedented separating capacity makes these approaches prime choices when analysts are challenged with highly complex mixtures. Furthermore, in the case of automated systems, instrumental analysis times are roughly the same as in monodimensional applications. The present review reports various comprehensive chromatographic applications on different food matrices. The GC x GC section highlights two fundamental aspects for component separation/identification: the exceptional peak capacity and the formation of group types on the 2D space plane. The LC x LC section reports the employment in food analysis of a recently developed multidimensional normal-phase (NP)-reversed-phase (RP) high performance liquid chromatography (HPLC) system. Also reported are comprehensive LC x GC and packed column supercritical fluid chromatography (pSFC x pSFC) applications in this field.     

Recent developments in microcolumn liquid chromatography.

An overview of the most recent developments in microcolumn liquid chromatography (LC) is presented. A short theoretical discussion on chromatographic dilution and extracolumn bandbroadening is given and also the recent progress and advances in column technology and instrumentation are reviewed. However, the emphasis of this review is on miniaturized sample clean-up, sample introduction techniques and on both established and more recent detection techniques for microcolumn LC. The hyphenation of miniaturized LC columns with other techniques, specifically on multidimensional chromatography and the coupling of microcolumn LC to mass spectrometry is discussed in detail. Both the on-line and automated off-line interfacing to other separation and detection techniques will also be addressed. Finally, a number of typical microcolumn LC applications are presented in order to demonstrate the potential of microcolumn LC methods in a variety of scientific areas.     

Comparison of chromatographic methods for hydrogen isotope separation by Pd beds

Comparison among three chromatographic separation methods, i.e. hydrogen-displacement chromatography, self-displacement chromatography and frontal chromatography, is made in an experimental way using several gas mixtures of hydrogen and deuterium. There is small difference in the height equivalent to a theoretical plate (HETP) based on the plate theory among the three chromatographic techniques. The HETP value for the self-displacement chromatography is 3.9 cm, and that for the frontal or H2-displacement chromatography is 3.0 cm at the same flow-rate. The self-displacement chromatography is more useful for the separation of a small amount of deuterium or tritium from other hydrogen isotopes under a moderate recovery ratio. Since the frontal chromatography uses no other gas than the sample, it is more convenient for the separation of deuterium from natural hydrogen even though a lower recovery ratio.     

Planar Chromatographic Systems in Pattern Recognition and Fingerprint Analysis

An overview of opportunities of contemporary planar chromatography in pattern recognition and fingerprint analysis is presented. The most used chemometric methods are highlighted and their main advantages and drawbacks are underlined. In addition a cross section of the application of planar chromatographic fingerprinting in food, pharmaceutical, environmental, and forensic analysis is given.