1290 Infinity II High-Speed Pumps User Manual 59
3Using the Pump
Solvent Recommendation for Agilent 1290 Infinity and 1290 Infinity II and 1260
Infinity II Flexible Pumps
Normal Phase Applications
Valves for Normal Phase Applications (G7120A)
Current passive inlet valves and outlet ball valves used with Agilent Infinity and
Infinity II pumps do not work well while running nonpolar solvents for normal
phase applications (for example, hexane and heptane). With such applications,
pressure drops could be observed. They are the result of particles in insulating
solvents, electrostatically charging up, and sticking to the nonconductive ruby
balls inside the standard valves, such that the valves no longer close properly
(could take just hours). For normal phase applications, a second type of valve is
available. These valves use a new material for valve balls, which is a conductive
ceramic. The ceramic balls do not charge up electrostatically and show good
performance in normal phase applications. The valves are marked with "N" to
stand for normal phase. Agilent recommends using these valves for (and only
for) normal phase applications.
To avoid changing to the Type N valves when running critical solvents, it is
possible to increase the conductivity of the mobile phase, by adding 5 % of a
miscible, polar solvent. In general, isopropanol is a good choice.
No design change has been done for active inlet valves, which have already been
used successfully for normal phase applications in 1260 Infinity I/II pumps.
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