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Question: |
Why does my companion over pressurises?
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Answer: |
The most likely cause it that one of the compounds in the mixture has crashed out. There are a couple of ways to avoid this. 1. Make sure the starting solvent is the same as the loading solvent (solvent used to disolve the mixture). 2. Use prepacked solid load cartridges and dry it down on a vacuum. 3. Disolve and dry the mixture down on lose Silica and then load in to an empty solid load cartridge.
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Question: |
What is the maximum flow rate and pressure
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Answer: |
Max flow rate: 100ml/min, Max pressure: 50psi
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Question: |
300psi max?
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Answer: |
No, Max pressure only 200 psi./
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Question: |
I need to separate 50g of compound, how can I achieve this?
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Answer: |
CombiFlash Rf for 40mg to 33g or the CombiFlash Companion XL 12g to 150g. The upper limit for separation is assuming that the separation is a simple one (baseline separation between peeks) with loading at 10% of total column silica, therefore a 330g silica column can separate up to 33g. A more difficult separation may only allow a total sample of 5% or 1% of total column silica.
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Question: |
How do I load large quantities of liquid on to an XL?
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Answer: |
Using a Peristaltic Pump and Liquid injection pump adaptor (part number: 68-5244-052) it is possible to automatically load large volumes of liquid sample on to any size column. You can find details on this item in our eshop.
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Question: |
During TLC my products tend to streak on the silica plate, how can I stop this?
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Answer: |
The common method to stop streaking is to spike your solvents with TEA, ammonia hydroxide, acetic acid or TFA. However this causes additional problems as the modifier needs removing from the final fractions with the addition of potential reactions between the modifier and the target compounds. Therefore, it is highly recommended that you consider the use of the C18 flash column or any of the other suitable alternative media. Applications notes on the alternative media can be found at www.combiflash.com
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Question: |
My compound doesn’t seem to be picked up by the CombiFlash system, what’s going wrong?
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Answer: |
If we assume the system is in a fully functional state, then you must confirm that the target compound has a UV active component; this can be easily achieved using either an HPLC system with a UV detector or a UV-Vis spectrometer. If the compound is confirmed to be UV active, then it has to be assumed there is a problem with the flow cell. This could include a dirty flow cell which can be cleaned following the cleaning procedure, found in the Technical Notes section. Or require a service call.
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