Pressure Injection Cell FAQ

Overview	FAQ	Purchase	Accessories

Specifications

Does the Pressure Injection Cell require electrical power?

No. The liquid sample is forced through the capillary using pressurized gas typically supplied by a tank Models with an integrated magnetic stirplate require electricity. They use a small power supply that plugs into a wall outlet. We supply the correct plug for your country.

Which gases can it use?

The choice of gas is not critical. Most customers use inert gases such as helium, nitrogen or argon. Dry air is fine too - if you purchase an adapter, NIP-AIR, to interface the tank with the pressure regulator.

Which adapters do I need?

If you're operating the pressure injection cell with inert gas in the United States or other country using English parts and CGA fittings (580 for inert gases), you do not need any adapters.

If you will use metric stainless steel tubing, you will need an adapter, ADPT-3mm1/8 to mate the 3 mm tubing with the 1/8 inch fitting on the pressure injection cell. This can be factory installed or installed in the field.

If you will use 1/8" stainless tubing with a regulator with metric or ISO fittings, you will need the adapter, ADPT-ISOto1/8.

Operation

How much pressure is required?

Loading samples into a capillary for mass spectroscopy typically requires 100 to 400 psi. Packing capillary columns typically requires 500 to 1000 psi.

Do I need a special pressure regulator?

Most pressure regulators for gas cylinders have a maximum working pressure that is too low for packing capillary columns. We sell a higher pressure regulator, model HPREG, that has a working pressure up to 1500 psi, which is ideal for packing standard length capillary columns.

How can you determine the approximate flow rate through a capillary?

If the solution is flowing only through an otherwise empty capillary tube, the flow rate is straightforward to calculate. However, a frit or a packed capillary typically causes much more flow resistance, so it is best to measure the flow rate with a test solution.

To measure the flow rate, run a test solution through a sample capillary and at the outlet place a calibrated micropipette. The solution should wick up the micropipette on its own so you don't need any special fittings to seal them together. For example, Drummond and other brands of micropipettes, available from most laboratory product suppliers, come in 1, 2, 3, 4, 5, 10, 20, ... &mico;l volumes. Using a stopwatch, measure how long it takes from when the solution starts to exit the capillary and begins filling the micropipette until the micropipette is filled.

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