Chromatography Forum

Any suggestion for the reliable pump(prefer no pulsation) for post column dye complexation method? Thanks.

Pickering Laboratories has a syringe-pump design in their high-end model http://www.pickeringlabs.com You may want to consult with them about your application, they are very knowledgeable and helpful.

Thank you for the information. I did contact Pickering, however the only one they have for pulse free syringe pump can not be sold alone. The whole package will cost $20K, which is not feasible for a simple application. I'm just wondering if there is any simple syringe pump with continuous flow.

CQ_32,

Post column, low pressure? If so, Cavro makes syringe pumps, as do Harvard instruments. These might suit your needs.

Best regards.

Other ideas - try a pulse damper - one can be constructed with a T connected to a partially filled syringe.

Another way which is competely pulse free is to use gas pressure connected to a pressurised container filled with the liquid and a suitable pressure valve. I think Omnifit could advise you.

Gas-powered post-column reagent delivery systems have been introduced in the market several times, and they always fall flat after a few years. I can only speculate as to the reasons. I worked for Pickering Labs for 9.5 years and those designs were never serious competition.

Mechanical pumps, while more complex, are more versatile, safer, give more reproducible results. Mechanical pumps fall in to two categories: reciprocating or syringe. The reciprocating designs need a pulse-damper and/or multiple pistons. The syringe designs need intelligent control to synchronize fill and delivery with the HPLC program, but don't need pulse-dampers.

Pulse dampers only work against backpressure. The common ones need at least 500 psi to be effective.

Pulse dampers can be constructed to work at low pressure - they are often used in flow injection to damp the pressure fluctuations of a peristaltic pump. (search Analytical abstracts)

I agree pressure systems are not in common use but they can be readily constructed in the lab at low cost.

Being a little cynical I think manufacturers often prefer complex to simple solutions.

An example is NASA spent vast sums in devising a pen to work in outer space -the Russians used pencils!!

An old HPLC column also makes an excellent pulse dampner. I used one between the pump delivering my post column reagent and the t-piece connecting the two flows.

The Soviet cosmonauts and American astronauts both used and hated the pencils. The Fisher Space Pen, developed by private industry, elegantly solved the problem, cost only a few dollars, and rapidly became the favorite of astronauts and cosmonauts. You can still buy them at www.spacepen.com