Liquid-Liquid Extraction - horizontal or vertical shaking

[wan]

Hi,

I was wondering if anyone did any studies to investigate the difference in using horizontal or vertical shaking in liquid-liquid extractions for their sample preparations?

Thanks.

[Consumer Products Guy]

An angle is better ergonomics.

No, you don't have to shake it upside down south of the equator...

[wan]

I should clarify. My colleague found that when she uses a vortex mixer or a orbital shaker for her extractions, she obtained different recoveries.

Perhaps it is not more of the direction. Been thinking about the difference, given that speed and time of shaking are kept constant.

[Don Shelly]

Add ink to solvent. Vortex one aliquot and shake another. You will see a big difference is dispersion. Also, shaking causes the solvent to form droplets, which increases the surface area of the sorbent exposed to the matrix over a given length of time.

[bluejay]

For what it's worth, EPA method 552.2 (Haloacetic acid analysis in drinking water by liquid liquid extraction) has this to say on shaking:

"place on the mechanical shaker for 30 minutes. (If hand-shaken, two minutes is sufficient if performed vigorously)."

[Consumer Products Guy]

Wow, I hope our QA department doesn't see this topic, could provide them "job security" for years !!!