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Thin Layer Chromatography
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Łukasz Cieśla, Monika Waksmundzka-Hajnos, Joseph Sherma
Most modern HPTLC quantitative analyses are performed by in situ measurement of the absorbance or fluorescence of the separated zones in the chromatogram tracks using an optical densitometic scanner (Reich, 2003; Sherma, 2001b; Spangenberg, 2015) operated with a fixed sample light beam in the form of a rectangular slit. The length and width of the slit is selectable for optimized scanning of spot or band-shaped zones with different dimensions. The densitometer measures the difference between the optical signal from a zone-free background area of the plate and that from the calibration standards and sample zones. With automated zone application, precision ranging from 1% to 3% RSD is typical for densitometric analyses. The plate is mounted on a moveable stage controlled in the X- and Y-directions by a stepping motor, which allows each chromatogram to be scanned, usually in the direction of development. Figure 30.17 presents a commercially available Camag TLC Scanner 4 enabling the densitometric evaluation of thin layer chromatograms. Desaga also offers a TLC scanner, available under commercial name HPTLC Densitometer CD 60.
Thin-Layer Chromatography in the Study of Entomology
Published in Bernard Fried, Joseph Sherma, Practical Thin-Layer Chromatography, 2017
Improvements in techniques and equipment, as well as the ready availability of high–quality plates with uniform layers have extended and increased the use of TLC in entomological studies, offering the possibility of quantitative, as well as qualitative analysis. High performance thin-layer chromatography (HPTLC), in particular, has developed to the extent that separation and quantification can provide results that are comparable with other analytical methods such as HPLC.8 In addition, TLC can offer a number of advantages to the researcher when used for the analysis of insect tissue extracts. Sample preparation, for example, may be simplified in many cases, since contamination of the stationary phase is not generally a problem. Multiple samples can be run simultaneously, a benefit in many studies because of high variability between individual insects. Detection procedures may be simplified as well. The process of detection is separate from that of plate development, such that incompatibility problems between solvent systems and detection methods are not a factor. The process of densitometric scanning can also be manipulated to improve results. Scans can be repeated for all or part of the chromatogram, without the need to rerun samples. This characteristic of TLC permits the use of additional detection techniques between scans that can aid in the identification of unknowns. Finally, one of the most important factors for entomologists is the relative ease with which very small extract solutions obtained from small samples can be handled and quantified.
Microbial Degradation of Coal into a Value Added Product
Published in International Journal of Coal Preparation and Utilization, 2019
The n-Hexane extracted supernatant was run in duplets on TLC plate and was scanned in HPTLC scanner at 247 nm. The defined peaks at this wavelength indicate presence or production of some phenolic acid-like compounds (Figures 1 & 2). High-Performance Thin-layer Chromatography (HPTLC) technique is a sophisticated and automated form of the thin-layer chromatography (TLC) with better and advanced separation efficiency and detection limits and is often an excellent alternative to GC and HPLC. HPTLC is an universal method for analysis and measurement of the phenolic acid compound. (Fong et al. 2006; Orazio, Kapila, and Manahan 1983). Production of phenolic compounds is indicative of biodegradation of coal to humic substances. The separation and determination of phenols are important in assessing and evaluation of samples from coal conversion processes in environment pollution studies. Coal-derived products are extremely complex mixtures and very little information is available on their chemical composition (Szepesy, Podmaniczky, and Szebenyi 1987). HPTLC has been used as a technique to obtain distinct fractions from coal liquids.
Development and validation of novel HPTLC method for the simultaneous estimation of Amlodipine Besylate and Telmisartan in tablet dosage form using ICH Q2 (R1) directions
Published in Journal of the Chinese Advanced Materials Society, 2018
Tomleshkumar B. Deshmukh, Sujata S. Deo, Farhin S. Inam, Trimurti L. Lambat
To the best of our knowledge, no efforts have yet been made to examine this drug combination by any HPTLC method. In the present study, attempts were made to develop and validated rapid, precise and accurate new method for simultaneous estimation of AMB and TEL in the pure form and a commercially marketed formulation. Now a day HPTLC is becoming a routine analytical technique due to its benefits of minimum sample preparation, high sample output and low operating cost. The major improvement of HPTLC is that numerous samples can be run simultaneously using a small quantity of mobile phase thus saving the analysis time as well as cost per analysis.[20] The proposed method was validated according to ICH guidelines.[21]