Syringe Pump

What is a syringe pump?

A syringe pump uses a motor-driven mechanism to push a syringe plunger at a precisely controlled rate.

In mass spectrometry it is commonly used for direct infusion.

Direct infusion

The sample is loaded into a syringe and connected to the ion source using suitable tubing.

Syringe → syringe pump → capillary/tubing → ion source → MS

The pump advances the plunger continuously, producing a relatively constant liquid flow.

Applications

Syringe pumps are useful for:

• tuning instruments

• optimising source parameters

• infusing standards

• studying fragmentation

• method development

• investigating ionisation behaviour

Advantages

Direct infusion is simple and provides a continuous signal, making it useful when adjusting MS parameters.

Limitations

There is no chromatographic separation.

All components enter the ion source together, which can produce:

• ion suppression

• overlapping spectra

• contamination

• difficulty distinguishing isomers or coexisting compounds

Important parameters

The most important parameter is flow rate.

The appropriate rate depends on the ion source and experimental setup.

Tubing internal diameter, syringe size, sample concentration and solvent composition can also influence performance.

Common problems

An unstable signal can result from:

• air bubbles

• blocked tubing

• leaking fittings

• an empty syringe

• unstable electrospray

• inappropriate flow rate

Key takeaway

A syringe pump provides controlled continuous sample delivery and is especially useful for direct-infusion experiments and instrument optimisation.