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LC Flow Splitters - how can we help?

11 May 2022

We have fixed and adjustable QuickSplit Flow Splitters for LC, designed to be used post-column. We have two types of these, binary fixed and adjustable ones. All of our splitters can accommodate a total (incoming) flow rate range of 0.1—5.0 mL/min. The ones that we sell are to be used with analytical columns (not semi-prep or prep scale columns). They have low dead volumes and can be mounted as needed.

Binary fixed flow splitters are available for 5 different split ratios, each with a unique catalog number. In each of these, there is a resistor that determines the split ratio. You can purchase replacements for these resistors if they become worn over time or to switch to a different split ratio.

Binary fixed flow splitters

Catalog #

Split ratio

*Resistor Catalog#
















*Resistors can be used to replace a resistor for the same or different ratio. The specified catalog number results in the corresponding split ratio from this table.

We also have Adjustable flow splitters that can be adjusted to cover a particular range of flow rate split ratios. Similar to the binary type, there is a resistor for each of these that determines the range of flow rates for the splitter.

Adjustable flow splitters

Catalog #

Split ratio range

**Resistor Catalog#


5:1 to 100:1



1:1 to 20:1


**Resistors can be used to replace a resistor for the same split ratio range or a different/new range.

There are Vernier scale markings on the knob for adjustable splitters, which enable the analyst precise control of the split ratio:


Documentation will come with each flow splitter that shows a corresponding split ratio for each setting marked on the Vernier scale. It would look something like this:


For routine use, you can simply set the split ratio to the desired settings by turning the knob to the scale setting that corresponds to the desired split ratio. It is important to keep the above document for reference in doing this. Accuracy of the split flow should be within 10% of the predicted value.

For applications that require higher accuracy, it is recommended to fine tune the split flow by measuring the time and volume with a graduated cylinder and stopwatch. It is also recommended to record the system backpressure at each measured setting and plot a curve of pressure vs. flow rate for each column, as well as the LC system with no column installed. The total system pressure is comprised of the column backpressure plus the backpressure across the splitter. Backpressure of the splitter will vary somewhat, depending on the viscosity of the solvent(s), but the flow ratio should remain the same for a specific setting.

I hope this post has answered some of the questions you had about our flow splitters.

Thank you for reading.