Fittings for Tubing

Several different in-line fittings are available for connecting pieces of tubing. These include unions, On/Off valves, Metering valves, and Valves with several fittings.

In addition to the fittings listed here, PTFE fittings and valves that can be used to connect tubing to our chromatography columns are also available. They are listed here.


An On/Off valve is used to stop or allow flow. It is not useful for controlling the rate of flow; a metering valve should be used for that purpose.

An On/Off valve is usually placed at the column outlet when doing gravity-flow chromatography. Closing a valve at the column outlet will stop the flow and yet keep the column packing wet even if a leak were to develop. For medium-term storage of a packed column two valves are usually used, one at the column inlet and one at the outlet. This also helps to keep the column packing wet.

Both ends of these valves have tubing connectors. They are available for use with 1/16", 1/8" or 1/4" OD tubing. A reducing valve is also available which accepts 1/4" OD tubing on one end and 1/8" OD tubing on the other.

The only wetted material in these valves is PTFE (an inert, white fluoropolymer).

On/Off Valve Availability
Part No.DescriptionPrice
124492On/Off valve for use with 1/16" (1.6 mm) OD tubing.138.00
124490On/Off valve for use with 1/8" (3.2 mm) OD tubing.138.00
124502On/Off valve for use with 1/4" (6.4 mm) OD tubing.121.00
124496On/Off valve for adapting 1/4" (6.4 mm) OD tubing to 1/8" (3.2 mm) OD tubing.138.00



A Metering valve adds a flow control feature to the on/off valve.

Metering valves have a needle stem to allow for a fine adjustment of the flow rate as well as simple positive on/off control which does not affect the setting of the needle. This makes the flow adjustment reproducible, even if the flow needs to be temporarily stopped between experiments.

These valves are available either with fittings for 1/8" OD tubing or with one 1/4" OD fitting and one 1/8" OD fitting. The only wetted materials in these valves are PTFE and Kel-F.

A combination 3-way valve and metering valve is available as a Stream Splitting valve.

Metering Valve Availability
Part No.DescriptionPrice
124508Metering valve for connection to 1/8" (3.2 mm) OD tubing.215.00
124514Metering valve for adapting 1/4" (6.4 mm) OD tubing to 1/8" (3.2 mm) OD tubing.181.00



Various Multi-Port valves are available for use in-line.

The 3-Port T-Bore Valve is used for mixing, solvent selection, and flow diversion. It has 3 tubing fittings for 1/8" OD tubing. The T-bore in the valve allows any 2 or all 3 ports to be connected together.

The 4-Port T-Bore Valve is also used for mixing, solvent selection, and flow diversion. It has 4 tubing fittings for 1/8" OD tubing. The valve connects each fluid port with one of those adjacent to it.

The Stream Splitting Valve combines a 3-Port T-Bore valve with a metering valve. This valve has 3 tubing fittings for 1/8" OD tubing. The T-bore in the valve allows any 2 or all 3 ports to be connected together. One of the tubing fittings also has a needle valve. This allows the fluid stream to be easily and reliably split between 2 of tubing fittings.

Multi-Port Valve Availability
Part No.DescriptionPrice
1245203-Port T-Bore Valve. Has 3 fittings for 1/8" OD tubing.399.00
1245213-Port T-Bore Valve. Has 3 fittings for 1/4" OD tubing.410.00
1245224-Port T-Bore Valve. Has 4 fittings for 1/8" OD tubing.415.00
124422Stream Splitting Valve. Has 3 fittings for 1/8" OD tubing.603.00



Tubing Unions are used to simply connect 2 pieces of tubing together. The 2 pieces may be the same size or different sizes.

The only wetted material in the unions is PTFE and they are precision machined, rather than molded, connectors.


Union Availability
Part No.DescriptionPrice
124450Union, connects 2 pieces of 1/8" OD tubing.79.00
124456Union, connects 1/4" OD to 1/8" OD tubing.66.00
124462Union, connected 2 pieces of 1/4" OD tubing.66.00
124435Union, connects 1/16" OD to 1/8" OD tubing.66.00
124460Union, connects 3/16" OD to 1/8" OD tubing.66.00



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