Normal Phase Applications - Agilent Technologies 1290 Infinity User Manual

4
Using the Module
Solvent Recommendation for Agilent 1290 Infinity and 1290 Infinity II and 1260 Infinity II Flexible Pumps

Normal Phase Applications

Valves for Normal Phase Applications
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.
Seals for Normal Phase Applications
For running normal phase applications on Agilent Infinity and Infinity II
pumps, yellow PE seals are required as piston seals. By default, 1290 Infinity,
1290 Infinity II, and 1260 Infinity II Flexible Pumps use ceramic pistons and
yellow PE seals as piston seals. 1260 Infinity I/II pumps use sapphire pistons
and black PTFE piston seals in a standard configuration. If using black PTFE
seals with normal phase applications, the black PTFE seals wear and generate
small particles. Such particles can clog valves and other parts in the flow path.
When running normal phase applications on 1260 Infinity I/II pumps, the
piston seals have to be changed to yellow PE seals. For optimum performance,
PE seals should be replaced during preventive maintenance.
1290 Infinity Quaternary Pump User Manual 85