Why do we draw a line with a pencil while conducting paper chromatography?

It’s pencil because solvents don’t interact with the graphite, so the pencil line won’t move up the plate. Your starting spot will move. You make this starting line high enough so it won’t get submerged in the liquid solvent liquid as you develop your plate.

Why must the line of origin be drawn in pencil and not ink?

Why must the line of the origin be drawn in pencil and not ink? The ink is made of different substances and would separate into different pigments and interfere with the experiment.

Why is it important to use a pencil to draw the line on the TLC plate and not a pen?

Do not use excessive forces when writing on a TLC plate as this will remove the stationary phase. It is important to use a pencil rather than a pen because inks commonly travel up the plate with the solvent.

Why do you have to make sure the paper line is above the water?

The reason for covering the container is to make sure that the atmosphere in the beaker is saturated with solvent vapour. Saturating the atmosphere in the beaker with vapour stops the solvent from evaporating as it rises up the paper.

Why is it important to use pencil when drawing the spotting line on your chromatography paper instead of ink What would happen if you did use a pen?

Answer and Explanation: In paper chromatography, the starting line must be drawn with the help of pencil because the pencil lead does not dissolve in solvent, thus it will not affect the separation. The spots of the compounds are separated correctly.

Why must the pencil line be above the solvent?

The start line above the solvent level allows the solvent to move past the start line, carrying the dissolved samples along with it.

Why is it important when preparing your TLC chromatography to keep the spots above the solvent?

The solvent level has to be below the starting line of the TLC, otherwise the spots will dissolve away. Non-polar solvents will force non-polar compounds to the top of the plate, because the compounds dissolve well and do not interact with the polar stationary phase.

Why must the base line be placed above the solvent level?

Why was a pencil used to mark the chromatogram?

Pencil is always used to mark a chromatography plate (or paper) because ink may run and interfere with the chromatogram. Ensure the spot is dry before running the TLC plate.

Why is a pen not used for chromatography?

1) Pen ink contains colored pigments. If we use the pen to mark on the chromatography paper then these pigments will also move along with the solvent…

Why must the pencil line on the TLC plate be above the level of the solvent when placed in the developing chamber?

Why should the solvent be below the pencil line?

Why must the starting line be drawn with a pencil in chromatography?

Answer and Explanation: In paper chromatography, the starting line must be drawn with the help of pencil because the pencil lead does not dissolve in solvent, thus it will not affect the separation. The spots of the compounds are separated correctly. Why must the solvent level be below the Coloured spots in chromatography?

Why is the origin of a chromatography line above the solvent?

In thin layer or paper chromatography the origin should be above the solvent because it could otherwise wash the sample spot into the solvent trough. Similarly one may ask, why is a start line drawn in chromatography?

Why can’t I use pencil ink in chromatography?

Get Grammarly. Because ink is a mixture so will be separated into its individual components on the chromatography paper as the solvent front advances up the paper. In contrast graphite in pencils is not a mixture, neither is it soluble in the mobile phase, so will not be dispersed across the paper as the solvent front moves over the paper.

What does a chromatogram tell you?

The chromatogram is a plot of the signal from you detector over time. That signal relates to how much of the compound is coming out. It makes sense that the area under the peak is going to tell you how much of that compound was in the sample, but why do you need to draw the line?