mobile phase pressure in binary pump

[che313]

our agilent 1200 is conssited of binary pump concetd with 50x2.1 PFP propyl 5um coulmn.
mobile phase A is water with 0.2% formic acid & ammonium formate, mobile phase b is acetonitrile with 0.2% formic acid & ammonium formate. when A is 100% the pressure is more than 200 bar and when b is 100% pressure is 100 bar!!

Is this situation regular?
flow rate is 1 mL/min

[tom jupille]

The viscosity of water is higher than that of acetonitrile, so yes, the difference makes sense.

[bisnettrj2]

http://www.separatedbyexperience.com/ar ... C012_1.jpg

http://www.separatedbyexperience.com/ar ... C016_1.jpg

Tom's correct. For more information, see the links for charts with the properties of different solvents, including viscosity.

[che313]

thnx tom & bisnettrj2
but coulm output n this situation are differs, i.e. in water case it is droping and in acetonitrile it is jetting!!

[tom jupille]

water has a higher surface tension than does acetonitrile so the drops tend to "hang together" better.

[carls]

Sounds like your solvent lines have been crossed somewhere. Follow each line from the reservior all the way to the pump to ensure the system is plumbed correctly. Perhaps someone mistakenly plumbed A to B at either the degasser or the solvent selection valve