bufophil - 9-2-2014 at 11:30
Hi, My question is this ; What would you consider to be the best HPLC pump out there in the resale market ( Ebay)? I'm talking about a pump that
doesn't need software and has a minimal amount of digital circuitry. Basically, I'm talking about a pump with a variable speed motor. Also important
is the availability of parts. I've noticed that there are a lot of 'Waters Model 510' on the market. The Waters unit might be the perfect starting
point for a HPLC system, but........ I would appreciate your input, Thanks
benzylchloride1 - 11-2-2014 at 23:24
Hands down the Waters 510 and similar pumps such as the 590 and 600 are the best pumps. If you want to mix gradients I would buy an older Waters 600E
with controller if you can find the cable, it is basically a 510 pump without the controller bolted to the side. This would give you the capability of
having four pumps running at the same time. The two main caveats are: the cable can be hard to find and you will need a helium cylinder to sparge the
solvent with since the low pressure mixing does not work well with solvent containing dissolved gasses. Another nice thing about the 600's is that you
can hook them up to a computer if you so wish, but they are completely operational without one. Another option would be to buy up to 3 510's and
control them with a Waters 680 gradient controller, this would avoid the need for sparging for general work, unless you use a high concentration of
water since the mixing is done under high pressure. Have fun and good luck, this stuff can get a little bit expensive. I personally would buy a 484
detector, there are several for under $100 on Ebay, all they need are new lamps, which are the biggest consumable expense since they are about $300
for one.
bufophil - 12-2-2014 at 15:23
Thanks for responding. I'm digesting your information at the moment. I appreciate your your advice as to the detector, but I will have to to defer
that to a later date. My concern is the controller. Any TV repairman can fix an analog device, but digital is a whole 'nother story. What does the
controller do? It seems to me that it is nothing more than a timer that initiates the pump stroke ( which is fixed, I assume).
benzylchloride1 - 12-2-2014 at 23:51
The controller allows you to run gradient curves, which can be useful to separate complex mixtures, this is not possible using the analog controls
directly on the pumps. I would not worry about repair issues with the controllers, they are cheap and abundant since everyone has been ditching them
for the totally computerized systems.