System and method for automated split injection for capillary electrophoresis

A method for performing capillary electrophoresis, comprising:

• drawing a controlled volume of a sample into a sampling column using a pump, wherein the sampling column contains a buffer solution;
• actuating a plurality of valves to establish a fluid pathway between the sampling column and a separation column;
• introducing the sample from the sampling column into the separation column at a split ratio determined by the controlled volume of the sample relative to the buffer solution in the sampling column;
• applying a voltage across the separation column to perform electrophoretic separation of ions in the sample;
• and
• detecting the separated ions using a detector.

A capillary electrophoresis system for multi-ion analysis, comprising:

• a separation column having an inlet and an outlet;
• a sampling column connected to the inlet of the separation column, the sampling column defining a channel configured to hold a variable volume of a sample;
• a syringe pump configured to draw the sample into the sampling column and to control the volume of the sample in the channel;
• a detector positioned at the outlet of the separation column and configured to detect separated ions;
• and
• a valve arrangement configured to selectively connect the sampling column to a sample reservoir and to the separation column, wherein the valve arrangement is operable to achieve a variable split of the sample volume introduced into the separation column.