Difference Between High Performance Liquid Chromatography and Ion Chromatography

Ion chromatograph is actually a branch of liquid chromatography in essence, but because it separates anions and cations and polar substances, its detectors are also mainly conductance detectors.
It can be seen that the absorption detectors are very different, so they are gradually separated from liquid chromatography and become a branch of the chromatography method independently
.

The difference between ion chromatography and high performance liquid chromatography is mainly reflected in the two aspects of instrument structure and application range
.

1) Differences in instrument structure between ion chromatography and high performance liquid chromatography Both have solvent delivery systems, sample injection systems, detection systems and signal recording and processing systems, but due to the different mobile phases used in ion chromatography and high performance liquid chromatography , so the detection method and signal processing are also different, and there are some differences in each component
.

A.
Ion chromatography generally uses an aqueous solution of acid, alkali and salt as the mobile phase, and the system is required to be resistant to acid and alkali.
Therefore, non-metallic materials are usually used for ion chromatography devices
.

For example: Polyetheretherketone (PEEK) plastic is used as the pump body, flow path and valve body and other parts that require high pressure resistance, and PTFE or PEEK material is used as the detector, external pipeline,
etc.

Due to the difference in processing and strength, the compressive strength and precision of all-plastic materials are generally slightly lower than those of metal materials
.

High performance liquid chromatography generally uses organic solvents as eluents, so most of them use metal pump bodies, which are resistant to any type of organic solvents, but are prone to corrosion for acidic or basic mobile phases
.

With the wide application of high performance liquid chromatography in the biological field, in order to avoid the adsorption of metals on some biologically active substances, some high performance liquid chromatography instruments used in biology also use PEEK materials as the pump body, flow path and valve
.

In this field, ion chromatography and high performance liquid chromatography have a certain versatility
.

B.
Ion chromatography can be divided into suppressed type and non-suppressed type.
The suppressed type of ion chromatography with suppressor is widely used at present
.

There is no similar device for high performance liquid chromatography
.

The suppressor is similar in structure to the post-column derivatization system of high performance liquid chromatography, but the suppressor is one of the regular components of suppressed ion chromatography
.

Unsuppressed ion chromatography does not use suppressors, and is very similar to high performance liquid chromatography.
Some unsuppressed ion chromatography can sometimes use high performance liquid chromatography pumps, flow paths, and injection valves
.

C.
The detector is another major difference between ion chromatography and high performance liquid chromatography
.

High performance liquid chromatography often uses a UV-visible photometric detector; while ion chromatography generally uses a conductivity detector
.

2) The analytical objects of ion chromatography and high performance liquid chromatography are very different.
High performance liquid chromatography, as a widely used instrument in analytical instruments, is widely used in many fields
.

When using high performance liquid chromatography, the analyte is often required to have a certain photometric absorption, so high performance liquid chromatography can generally be used for the analysis of organic compounds
.

Ion chromatography mainly uses the characteristics of ionization of ions in aqueous solution to generate conductivity, so it is mainly used for the analysis of inorganic ions
.

Of course, the application of ion chromatography and high performance liquid chromatography is not without overlap.
At present, ion chromatography has been widely used in the analysis of organic compounds, and high performance liquid chromatography can also solve the analysis of a large number of inorganic ions.
The two separation modes have certain characteristics.
complementarity
.

Some analytical problems that cannot be solved by high performance liquid chromatography can be solved by ion chromatography
.