Experiment 9 thin layer chromatography
Of incidental interest, the marker lane 3 also shows the phosphatidylinositol PI and phosphatidyl glycerol PG bands.
Visualize the tlc plate in an iodine chamber. You will need this sheet to record your data.
Thin layer chromatography pdf
If samples of the separated materials were desired, the entire experiment could be scaled up to allow milligrams to be separated. Lack of attention to key steps can result in poorly developed plates. If the compound likes the stationary phase, it will stick to it, which will cause it to not move very far on the chromatogram. You can watch a video that shows how to use our centrifuges. An important modification to the original protocol from Helena involves step C6. The TLC plate was coated in a silica gel which acted as the stationary phase, which is the material that does not move. There are two simple ways of getting around this problem. Perform only in a well ventilated hood. Be sure the depth of solvent is no more than 0. Each team should construct a separate key on a piece of paper, identifying the substance to be introduced into each numbered channel lane on the TLC plate, including channels for marker, 1E, 2E, and 3E. Also, make sure that the TLC plate is placed in the chamber evenly. Figure 1 8 Stopper the chamber to allow it to become saturated with solvent vapors. In the two analgestic experiments, the two solvents used were ethyl acetate and acetic acid, and ethyl acetate and hexanes.
You will find a further link to van der Waals forces at the bottom of that page. The compounds present will then tend to get carried up the chromatography plate as the solvent continues to move upwards.
Similarly for bases, adding a few percent triethylamine can improve results. TLC plates do not have long stationary phases. Therefore the use of real samples does not provide any significant learning experience.
Geiss, Friedrich. An important modification to the original protocol from Helena involves step C6. A common starting solvent is hexane:ethyl acetate.
Thin layer chromatography lab report pdf
Be extra careful to keep the UV lamp pointed down at the bench top at all times. Conclusion In conclusion, TLC proved to be a successful method of identifying unknown compounds and determining the polarity of substances. An example of how black ink separates is shown in the section labeled "examples". List them and describe their appearance. Some similar problems are discussed on the page about paper chromatography, but I am unwilling to do the same thing on this page which is intended as a fairly gentle introduction to chromatography. In that case, changing the solvent may well help - including perhaps changing the pH of the solvent. It also prevents the evaporation of solvents and keeps the process dust-free.
The rates, aka the Rf values, differ due to the polarity of the solvent versus the compound, where the more polar the compound, the slower it moves up the plate, giving it a lower Rf value.
The spots would be visualized by UV non-destructive and then separately scraped from the glass plate. Figure 1 8 Stopper the chamber to allow it to become saturated with solvent vapors.
There is no need to measure the Rf values because you can easily compare the spots in the mixture with those of the known amino acids - both from their positions and their colours.
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