Retention factor values in thin layer chromatography are affected by the absorbent, the solvent, the chromatography plate itself, application technique and the temperature of the solvent and plate.
Q. What happens to RF values when you change solvents?
The eluting power of solvents increases with polarity. Non-polar compounds move up the plate most rapidly (higher Rf value), whereas polar substances travel up the TLC plate slowly or not at all (lower Rf value).
Table of Contents
- Q. What happens to RF values when you change solvents?
- Q. Why RF values are different?
- Q. Can RF values be greater than 1?
- Q. What is the principle of separation by paper chromatography What is the importance of RF value?
- Q. What 2 distances are important when calculating RF values in chromatography?
- Q. How do you calculate retardation factor?
- Q. Why is retention factor always less than 1?
- Q. What is the formula of angular retardation?
- Q. What is the difference between retardation and acceleration?
Q. Why RF values are different?
The larger an Rf of a compound, the larger the distance it travels on the TLC plate. When comparing two different compounds run under identical chromatography conditions, the compound with the larger Rf is less polar because it interacts less strongly with the polar adsorbent on the TLC plate.
Q. Can RF values be greater than 1?
Long Answer: Rf is the “Retardation Factor”, which is the ratio of the distance traveled by a compound in a mobile phase compared with the distance traveled by the front of the mobile phase itself. It is always greater than or equal to zero, and less than or equal to 1.
Q. What is the principle of separation by paper chromatography What is the importance of RF value?
The mechanism of separation in paper chromatography is mainly partition in Type. So, when a drop of the solute is treating with the solvent on the paper, the more strong components back while less strong components are move forward. The relative rate of the movement of solvent and solute is expressed by a term Rf.
Q. What 2 distances are important when calculating RF values in chromatography?
By definition, the Rf value is taken as the distance from the centre of te zone. This is however prone to visual estimation errors, so the best way to calculate the centre is to measure the following 2 distances: measurment from origin to the top edge of the zone, measurment from origin to the bottom edge of the zone.
Q. How do you calculate retardation factor?
The RF value (retardation factor) of a zone is the ratio of its migration distance to that of the mobile phase front. RF = MD/zf.
Q. Why is retention factor always less than 1?
Answer. Rf values are alwaysless than 1. An Rf value of 1 or too close to it means that the spot and the solvent front travel close together and is therefore unreliable. This happens when the eluting solvent is too polar for the sample.
Q. What is the formula of angular retardation?
The angular retardation in rads-2 is. Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams. or Angular retardation, α=ω0t=30π60rad s-2=π2rad s-2.
Q. What is the difference between retardation and acceleration?
Acceleration is the increase in velocity per second, while retardation is the decrease in velocity per second. Thus, retardation is negative acceleration. In general, acceleration is taken positive, while retardation is taken negative.
