Author Topic: TLC Time  (Read 9336 times)

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Rhodium

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Computer-Aided Thin Layer Chromatography
« Reply #40 on: May 01, 2004, 10:17:00 PM »
Identification of Pharmaceuticals via Computer-Aided Thin Layer Chromatography
Macherone, Anthony J., Jr.; Siek, Theodore J.

J. Chem. Educ. 77, 366-367 (2000)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/digi-tlc/p366.pdf)

Supplementary Info(PDF)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/digi-tlc/supp366.pdf)

Supplementary Data (ZIP)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/digi-tlc/supp366.zip)

Abstract
In toxicology laboratories, thin-layer chromatography (TLC) provides a quick and accurate method for qualitative identification of unknown biotoxins that may be present in a fluid or tissue sample. These varied samples are presented to the toxicologist for analysis on a routine basis and also during emergency situations or after a death. The ability of TLC to identify or rule out hundreds of compounds in a single analytical run makes it amenable to emergency toxicology and forensic chemistry. However, the ability to decipher the various reactions and elicit meaningful results from the raw data can take years of experience. It would be useful therefore, for analysts to obtain a firm background in TLC while still in academic training. This analytical laboratory experiment demonstrates the methodology of TLC in its relation to toxicology and forensic chemistry. It is easily adapted for high school seniors or undergraduates and employs experimental techniques associated with TLC and post-lab data analysis with concomitant introduction of concepts. The procedures are designed to introduce the student to the concepts, mechanisms, methodology, and reactions of TLC while building skills in record keeping, data analysis, and deductive reasoning.
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Rapid, Simple Quantitation in Thin-Layer Chromatography Using a Flatbed Scanner
Johnson, Mitchell E.

J. Chem. Educ. 77, 368-372 (2000)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/digi-tlc/p368.pdf)

Supplementary Info(PDF)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/digi-tlc/supp368.pdf)

Supplementary Data (ZIP)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/digi-tlc/supp368.zip)

IGORPro 5 Software

(http://www.wavemetrics.com/Products/IGORPro/IgorPro.html)

Abstract
A standard flatbed scanner is shown to be a viable tool for quantitative thin-layer chromatography (TLC) plate analysis. Simply scanning a visibly stained TLC plate into a computer substitutes for much more expensive plate readers. With common image analysis software, "elution" profiles can be obtained. The resulting "chromatograms" can be analyzed in the same manner as other chromatograms. Iodine-stained cholesterol and cholesteryl esters are shown to yield nonlinear calibration curves, but the overall sensitivity is excellent for such a simple method. Detection limits are submicrogram for heavily stained spots. Spot intensity, and therefore detection limit, depends strongly on the amount of time the spot is exposed to iodine. Reproducibility is excellent for spots deposited by aspiration from a glass micropipet. Peak area and peak height relative standard deviations (RSDs) were generally below 5%, and retention factor precision was as low as 0.8% RSD.


Rhodium

  • Guest
Comparative elution power of common solvents
« Reply #41 on: May 31, 2004, 05:22:00 PM »
What solvent mixture has the most eluting power? Petroleum ether/ethyl acetate (1:3) or is it chloroform/ethyl acetate (1:1)?

Use the table below to find out.




Rhodium

  • Guest
The Rf Value As A Constant In TLC
« Reply #42 on: September 30, 2004, 07:34:00 PM »
The Rf Value As A Constant In Thin-Layer Chromatography
J.H. Dhont

Journal of Chromatography. 202, 15-20 (1980)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/tlc.values.as.constants.pdf)

Summary
A comparison has been made of the results of a number of experiments concerning Rf values in thin-layer chromatography randomly chosen from the literature. The study led to the conclusion that in thin-layer chromatography a constant Rf value can be obtained.