Operational Hints For The Multi Channel Gradient Valve (Mcgv) - Agilent Technologies 1290 Infinity User Manual

5
How to Optimize the Performance of Your Module

Operational Hints for the Multi Channel Gradient Valve (MCGV)

Operational Hints for the Multi Channel Gradient Valve (MCGV)

In a mixture of salt solutions and organic solvent the salt solution might be
well dissolved in the organic solvent without showing precipitations. However
in the mixing point of the gradient valve, at the boundary between the two
solvents, micro precipitation is possible. Gravity forces the salt particles to fall
down. Normally the A channel of the valve is used for the aqueous/salt
solution and the B channel of the pump is used for the organic solvent. If used
in this configuration the salt will fall back into the aqueous solution and will
be dissolved. When using the pump in a different configuration (e.g., D - salt
solution, A - organic solvent) the salt can fall into the port of the organic
solvent and may lead to performance problems.
When using salt solutions and organic solvents it is recommended to connect the salt
N O T E
solution to one of the bottom ports of the MCGV and the organic solvent to one of the
upper gradient valve ports. It is best to have the organic channel directly above the salt
solution channel. Regular flushing with water of all MCGV channels is recommended to
remove all possible salt deposits in the valve ports.
Precipitations formed during the mixing of buffers and organic solvents which do not
N O T E
dissolve salts may cause a loss of pump performance (flow/retention time stability), a
blockage or internal leak of the pump. Avoid the use of such solvent combinations, as they
can cause irreproducible chromatographic results.
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