Chromatography Forum

I am in the Pharma industry and the usage of solvent is high, so that the idea is to save the money.

Do you think recycle HPLC mobile phase is possible? Most of our mobile phase are phosphate buffer, Methanol and Acetonitrile. Is it possible to distill methanol and reuse for the mobile phase?

Anyone had the experience?

I used to to a lot of prep lc work. We used to recycle the eluent straight from the waste as it was an isocratic system. Obviously we discarded anything that was contaminatated, which meant that it was only the eluent waste from the equlibration time or between runs.

GCguy

Well, no too much experience. Recycling of the eluent should actually the last thing I would think about.
For prep this may work, but for analytical I think it is risky. Especially when a method is validated.

Options that would make more sense, it to switch to Nano LC or work at elevated temperatures.

For analytical gradient work it is simply not worth the time and effrot. For isocratic UV work recycling is an option but over time there will obviously be an increase in background. For prep the case is not so straight forward. The volume of solvent generated as waste and the cost of its disposal must be weighed against the time taken, the energy used and the space required to purify this waste. So far it is still not economically viable but as enviromental concerns grow and the cost of disposal increases this may no longer be the case. The need to be, or appear to be, GREEN may out weigh the cost of course.

Having had considerable problems with some botched batches of commerzial solvents I would dislike to bother with stuff possibly adulterated by a column.

Our Shimadzu detectors are equipped with recycling valves, and we use these to conserve MP. We also have Eppendorf recyclers that are activated by the analogue output from any detector. This is useful if you plan to reuse the same mobile phase many times, or make up 1L instead of 4L. I don't think it is feasible to distill organic from a MP.
J

Thank you for your comments.

I surf the internet and find two ways of recycling mobile phase.

1. mobile phase recycler - for recycle mobile phase in isocratic HPLC mode. According to the catalogue, "The principle of MPR 010 operation is based on automatic switching of the flow between "waste" and "recycle" positions according to the actual value of signal, continuously monitored on the detector. The switching valve is positioned just past the detector, so that the flow can be directed from the "recycle" position into the "waste" immediately when the signal increases above a predefined threshold. The redirection from "waste" back to "recycle" mode can be delayed to account for the time needed to rinse the connection between the detector and the recycler.
http://www.laballiance.com/catalog/so14.htm

2. distill solvent such as methanol from the mobile phase and reuse
http://www.geocities.com/brinstrument/

The problems I concern are whether the background noise will increase after reuse the mobile phase and how many time it can be reused for the first way and I need to validate the recovered solvent when I reuse it for the second way.

I think both ways are possible but need to do assessment on the cost, safety and other quality issues.

vv, some, above, have already pointed out possible causes for detrimental changes of mp, so why don´t you just try out recycling, tell us precisely what you did and what you found.