THE CHROMATOTRON

Centrifugal Thin-Layer Chromatograph

 

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Chromatotron

 
The Chromatotron is a preparative, centrifugally accelerated, radial, thin-layer chromatograph designed by the authors of the Compendium of Organic Synthetic Methods. It replaces prep TLC plates, small columns and HPLC.

Overall dimensions are 30x35x30 cm.

 

 

 

Principle of Operation: The sample to be separated is applied, as a solution, near the center of a spinning disk coated with a thin layer of sorbent. Elution by solvent forms circular bands of the separated components which are spun off from the edge of the rotor together with solvent. A novel collection system brings the eluate to a single output tube.

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Capacity: Up to 500 mg per component, 1-2 g total, e.g. dimethyl and diethyl phthalate in hexane - ethyl acetate 9:1 on a 4 mm layer of silica gel.
Sorbents: Silica gel, alumina and silica gel - silver nitrate.
Not useful with RP sorbents.
Solvents: Compatible with all common chromatography solvents, including acetic acid.
Not suitable for use with mineral acids.
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Special Advantages:

* No "spotting" of samples or scraping of bands.
* Separations are completed rapidly, typically within 20 min.
* A UV transparent lid allows direct observation of UV absorbing or colored compounds during the separation.
* Layer thickness of 1, 2, 4 or 8 mm gives high capacity. The sorbent layer is easily regenerated in situ for reuse.
* Solvents are used sparingly. Gradient elution is easy. A nitrogen atmosphere prevents oxidation of samples.
* Compact (easily moved from lab to lab), few controls, no high pressures.
* Low price. Half a dozen Chromatotrons cost less than a single prep HPLC.

 

Compounds without a chromophore are detected in the eluted fractions by conventional TLC.
Connection to refractive index and UV monitors is not recommended.
May be used with a fraction collector although hand collection is adequate.

 

References:

For applications, search for chromatotron on the Internet. Several thousand applications of the Chromatotron can be located by a Google Scholar search for chromatotron. Refine your search by including the specific substance or general class, e.g:

chromatotron alkaloid

chromatotron glycoside

chromatotron ibuprofen

chromatotron antioxidant

chromatotron enzyme inhibitor

chromatotron hiv inhibitor

chromatotron medicinal plants

 

               Examples of Separations

1 Cyclopentanone and cycloheptanone 2,4-dinitrophenylhydrazones, 4 mg, on a 1 mm layer of silica gel. A UV monitor was used for detection. This monitor is not supplied and is not required for operation of the Chromatotron.

 

 

 

2 Strychnine and brucine (250 mg) on a 2 mm layer of silica gel. A UV lamp was used for detection. Bands on rotor are shown full size.

3 Dimethyl and diethyl phthalate (1 g) on a 4 mm layer of silica gel.




Comments from Chromatotron Aficionados
With the Chromatotron we can purify in 15 minutes and spending no more than 300 mL of eluent up to 1.0 grams of sample. The system is extremely efficient.
The Chromatotron is indispensable in my work. I may never use my MPLC again, and I certainly will never do linear thick layer chromatography ever again.
I'll second A-non-y-mous regarding the Chromatotron. It's still one of my favorite lab tools. Separations equal to flash but more convenient. Much more convenient and faster than prep HPLC.
Radial Chromatography (aka Chromatotron)-it really was indispensable for my graduate work (bile pigments), and works 10x better and quicker than a column.
When it comes to wacky lab equipment, I have to admit that the Chromatotron is one of my favorites. It is essentially a radial prep TLC accelerated by centrifugal force. Other than speed, the other advantage over prep TLC is that you don't have to scrape your products off the plate. Instead, you collect fractions out of the bottom like you would from a column. The best part is saying "Chromatotron" in your dissertation defense with a straight face.
Ah, the Chromatotron. One of my favorite memories from PhD land was fixing the UV lamp from the UV cabinet above the Chromatotron late one night, to allow me to visualize the bands of anthracene derivatives as they eluted from the plate. Brilliant blue ever widening circles. Beautiful.
The Chromatotron is obsolete? Say it ain't so! I used one the other day to separate 100mg each of 2 diastereomers. Sure, it is a glorified record player, but it does the job (and generates some great expressions from folks who have never used one).
I recently had occasion to use a Chromatotron that you had repaired for Dr. A. McK. I used it to separate geometric isomers, and it turned what is a painful separation by column chromatography into an easy and painless one. So, I am truly a convert, and I have to have one.
The instruction manual is excellent; so is the Chromatotron.
You have a Chromatotron? I used to use one of those myself; I'm glad that they're still around.


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