Dear Punnam,

The Wikipedia and Instructables references don't give you quite enough information. If you already have the silica gel and calcium sulphate binder (simply makes the stationary phase harder and stick better to the glass) you might wish to follow the procedure (modified by me regarding weights and volumes) briefly described by Harborne (1998) Phytochemical methods, 3rd edition, London: Chapman and Hall, p11. A slurry of silica gel (30g) and calcium sulphate (4.5g) in water (about 60mL) is shaken vigorously for around 90 seconds and then applied to glass sheets (previously cleaned with acetone). These are allowed to dry and then activated by heating at 100-110“C for around 30 mins. Small plates are perhaps easier to prepare.

The 5th edition of Vogel's textbook of practical organic chemistry (p220) contains more information.

Also very useful is Houghton and Raman (1998) Laboratory Handbook for the Fractionation of Natural Extracts, London: Chapman and Hall. pp150-151.

Hope this is of some help.

The silica gel remains as a suspension i.e. it does not dissolve.

http://en.wikipedia.org/wiki/Thin_layer_chromatography#Plate_preparation

The following website tells you every detail of plate preparation. It does not require expensive tools.

Good luck with the experiments!

Dear Silica gel will not disolve. You first make slurry (thick paste) of silica gel and calcium sulphate and then spread it on the plate with the help of spreader, dry and use. But ready made plates are also available from scientific store if you use that plates it will be much better for your research.

Dear Punnam,

The Wikipedia and Instructables references don't give you quite enough information. If you already have the silica gel and calcium sulphate binder (simply makes the stationary phase harder and stick better to the glass) you might wish to follow the procedure (modified by me regarding weights and volumes) briefly described by Harborne (1998) Phytochemical methods, 3rd edition, London: Chapman and Hall, p11. A slurry of silica gel (30g) and calcium sulphate (4.5g) in water (about 60mL) is shaken vigorously for around 90 seconds and then applied to glass sheets (previously cleaned with acetone). These are allowed to dry and then activated by heating at 100-110“C for around 30 mins. Small plates are perhaps easier to prepare.

The 5th edition of Vogel's textbook of practical organic chemistry (p220) contains more information.

Also very useful is Houghton and Raman (1998) Laboratory Handbook for the Fractionation of Natural Extracts, London: Chapman and Hall. pp150-151.

Hope this is of some help.

Dear scholar, the silica gel does not dissolved in any solvent. you have to make a slurry with distilled water (appropriate ratio) and pored, spread with out air bubble with help of spreader (any other) to the clean glass plate as a thin layer. after air dried the plate, activated with hot air oven at 50-60 degree centigrade for 15-30 mins (you can use microwave oven also). The activated plate cooled at RT, then you can prepare solvent tank and load the sample and run with respective solvent system of your samples.

If the compound colored mean you can visualized directly, if not (colorless) you can you use iodine chamber for visualization.

Dear Punnam,

Silica gel is absolutely insoluble in any medium. what you have to do is suspend it in water and ensure that are absolutely no lumps at all. The ideal consistency of the suspension is that it should not be free flowing, it should not be like cement, and it should have been soaked in water long enough (about 30 min is enough) to be completely hydrated. if you have a TLC spreader, use it to spread the plate to appropriate thickness. if not, you can place some silica gel slurry in the centre of the plate and rock the plate till the silica gel reaches all corners. this is a bit messy so always cover your desktop with paper. place the plate at room temperature to dry to the point that it does not flow anymore. after that, take the plate and place in a hot air oven to dry. the temperature of grying depends on whether you want to perform partition chromatography (~80 C) or adsorption chromatography (~ 110 C). Look up the relative merits and demerits of these two techniques.

Like every experiment, its most necessary to be clear about what you want to know. the way ahead from there is relatively easy. Another thing, i would advise you to simply use commercial silica gel-G. Do get back to me if you have more to ask. ([email protected]).

All the best

Samir

Hi dear.. U can go for maker the slurry by using water and along with you can add acetone.

hey, silica gel is not soluble in water. For tlc now-a-days precoated plates are being used as they are ment for documentation and also can be cut into required dimensions according to the number of spots u wanted to load.

in simple lab techniques, silica gel: distilled water to the ratio of 70:30 will give you a good slurry, which can be spread over the simple microscopic glass slide which is used as a base. the coating can be done in 4 methods like dipping, spreading, pouring and spraying of which spreading is the best method. but be careful that the uniform layer should be attained. this is the main problem with manual plates, so precoated plates are best suitable. calcium sulphate is the binder, check for the "silica gel used for TLC" this is suitable.

regards

Sirinagaraj

Hi, chromatographer!

Everything that was told above, truly. I will add only one comment. For preparation of analytical TLC-plates it is better to use silica gel with the size of particles 5 - 20 microns. Proportions of silica gel and solvent (water, sometimes with addition of organic solvent) it is possible to find in books on TLC. Such suspension is well smeared on plates.

They well and in regular intervals dry up and give an equal smooth surface. It is possible to obtain qualitative enough self-made plates with a thin layer of silica gel.

Dear Punnam Chander,

I would like to make it clear that your concept of dissolving adsorbent (Silica Gel) for making TLC plate is wrong. In TLC, the homogenized slurry of preferred adsorbent is coated on a substrate (glass plate or aluminium sheet) with the aid of TLC applicator (for better accuracy) or manually pored for uniform spreading. So what you require here is a wet slurry of Silica Gel60-120 for spreading on the substrate.

Since you want to impregnate (Here I guess you want to impregnate Silica Gel with Calcium Sulphate) the slurry, first prepare a solution of calcium sulphate (say 0.1 to 5%) according to your requirement and use that solution for making slurry of silica gel ( say add ~ 35 gm silica gel and 90ml aqueous calcium sulphate solution and mix it well by constant shaking or with a glass rod in a conical flask of 250ml capacity). Ensure no lumps and bubble formation during the preparation of slurry. The homogenized slurry is now ready for pour on to clean dry glass plates (10 x10 cm; 15 x 3 cm; 2.5 x 7 cm, 20 x 20 cm etc) size according to your choice.

Dry the plates at room temperature and activate in an electric oven. Preserve in airtight chamber for TLC. Calcium sulphate impregnated silica gel plates are ready for TLC.

Is it simple now…?

You can also try dip method. Dissolve silica in a volatile solvent (chloroform). Take a glass plate and dip into it and dry. Now it is ready for use.

i think we have given enough replies to this. he has enough to make a TLC plate now.

Silica 60-120mesh is for column chromatography, not for TLC. Use Silica G for TLC

use silica gel meant for TLC ....60-120 MESH SIZE is used for open column the particale size large....get tlc silica

Not exactly..please refer http://85.238.144.18/lifescience/literature/061009_Making_TLC_Plates_from_Bulk_TLC_Silica_Gels.pdf

Readymade (precoated) TLC plates are also available....

Thank you all for sharing you ideas. I am out of station and after reaching to my institute I will try with these methods and let you know the result....

The suggestions on silica gel need to be considered, varieties such as H, G, H254 , G254 etc., meant exclusively for TLC are available and marketed by Merck, Qualigens, Fischer, Loba, SD Fine etc.

Its damn easy ,make the paste sort of and pour it ,rub it on a surface to meke the layer uniform

Hello, I hope your silica gel is in powder form. Take 10 parts of silica gel and 1 part of CaSO4.1/2 H2O (it acts as binder for silica gel on plate). Make a slurry of the mixture and proceed as you have been doing. Note that glass plate if free of any greasy contamination. Good Luck.

Dear sir, first take some amount of silica power in a beaker and add some amount of water and star well 15 mint and add water for needed and make salary type past and this salary or past fallow on TLC plate before arrange plate slop type fallow of past top of the plate some amount and give vibrate to plate till equivalent thickness of past on whole plate and dry to this TLC plate at 105C in oven for 1hour. and now use of this TLC plate for separation technique.

Dear sir,

Please weigh about 5-6 gms in 10ml of DM water mix well with help of stoppered iodine flash for few minutes then remove the stopper weight few seconds & pour immediatelyon the glass plate, make quikly with help of spreader then remove and keep in oven for i hr at 105*c after dried , normal procedure of sample injection to be followed and keep in well prepared mobile chamber to travel upwared direction and must line marked on the gel coated plate to avoid over flow the mobile phase.

Dear sir,

Please weigh about 5-6 gms in 10ml of DM water mix well with help of stoppered iodine flash for few minutes then remove the stopper weight few seconds & pour immediately on the glass plate, make quikly with help of spreader then remove and keep in oven for one hr at 105*c after dried , normal procedure of sample injection to be followed and then keep it in well prepared mobile chamber to travel upwared direction and must line marked on the gel coated plate to avoid over flow the mobile phase.