Question

in chromatopraphy, Give an example of stationary phase in your Bu HSSSSS The following questions are for Exp. Microfluidics (Chromatography). 1 Briefly explain about stationary phase in chromatography. Give a chromatography experiment. (1 pt) Statinca a dop Phese is when you but a anor and does not spread as easily ore epauple wall Nac. 2. Briefly explain about mobile phase in chromatography. Give an example o chromatography experiment. (1 pt) mobile Phase is when dos spreads over water was mophe sure it spread pay. Give an example of mobile phase in your more easily Give a formula of relative retention factor, Rf, in chromatography. (1 pt) Moblem I da distance Bronx Of Colored What is Rf, relative retention factor if you get the distance of a component of a mixture, 85 mm, and the distance of mobile phase, 100 mm. (1 pt) 4 Rf = adue Gas 5 cc opet se Gas ③ NR 4 CC Spurple/ ppt NR NR I GAS

Answer 1

1. The stationary phase consists of finely grounded adsorbent materials like silica gel (SiO₂) or alumina (Al₂O₃) which are uniformly coated on a glass sheet or a metal foil. (say in Thin Layer Chromatography, it is known as TLC plate). In the normal phase chromatography, the stationary phase is more polar than the mobile phase. The more polar component of the mixture interacts more with the stationary phase, spends more time in the stationary phase and hence this component travel less on the TLC plate.

2. The mobile phase in chromatography consists of a highly pure solvent or a mixture of solvents. In the normal phase chromatography, the mobile phase. is less polar than the stationary phase. The less polar component will have a higher affinity (more intermolecular attractions) to the mobile phase and travel fast and farther.

The careful selection of proper solvent (mobile phase) by trial and error is the key step in TLC. In general,1:1 ratio of hexane: ethyl acetate is used as a common starting solvent in TLC and then the ratio can be varied for better separation.

Polarity of solvents: Hexane < ethylacetate < acetonitrile < propanol < methanol < acetic acid < water.

3. The retention factor (R_f) is defined as the ratio of the distance traveled by a component to the distance traveled by the solvent front.

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of Distance teavelled by a Component Distance travelled by solvent front 0 Giren Distance travelled by a component= 85 mm Distance travelled bing mobile phose = lo mm .: Rp = 85 mahe Scanned with CamScanner