Current passive inlet valves and outlet ball valves used with 1260 and 1290 Infinity pumps do not work well with applications using non-polar solvents as for normal phase applications (e.g. hexane, heptane and CO₂). With such applications, pressure drops could be observed. They are a result of particles electrostatically charging up in insulating solvents and sticking to the balls inside the valves, such that the valves do not close properly any more after some time of use (can be hours).
For normal phase applications, a second type of valves is available, which has a design based on the existing one for 1260 and 1290 Infinity valves. These valves use a new material for valve balls, which is a conductive ceramic and replaces non-conductive ruby balls. The balls do not charge up electrostatically and show good performance in normal phase.
The valves are marked with N for non-polar or normal phase.
Agilent recommends using these valves for (and only for) normal phase applications.
CAUTION
Corrosion of valves
Normal phase balls/valves corrode quickly in aqueous solutions and acids (at or below pH 7).
The N-Valves have been tested successfully in using hexane at pressures below 100 bar; heptane can be used as a substitute for neurotoxic hexane.
For running normal phase applications on 1200 Infinity Series pumps, yellow PE seals are required, which exist as piston seals and wash seals. Seal wash is very uncommon for normal phase applications (no buffers needed), but wash seals are needed for seal wash pump heads.
1290 Infinity pumps use PE seals by default. In combination with ceramic pistons, PE seals are used for both reversed phase (1200 bar) and normal phase applications.
1260 Infinity pumps use sapphire pistons and black PTFE piston and wash seals by default (600 bar). Such PTFE seals create small wear particles in normal phase applications, which can clog valves and other parts in the flow path.
PE seals have a limited life time when used with normal phase solvents and sapphire pistons. Agilent recommends a maximum pressure of 200 bar for this combination, which shall also be applied for pressure tests.
| 1260 Infinity | 1290 Infinity |
|---|---|---|
Inlet valves | G1312-60166 (1260 Inlet Valve Type N) | G4220-60122 (1290 Inlet Valve Type N) G4204-60122 (1290 Quat Inlet Valve Type N) |
Outlet valves | G1312-60167 (Outlet Valve Type N/SFC) | G4220-60128 (1290 Outlet Valve Type N) |
Seals | 0905-1420 (PE seal (pack of 2)) 0905-1718 (Wash Seal PE) |
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