TEA is an organic base and hence is sometimes used in some HPLC methods to adjust the mobile phase pH. Our research has indicated that TEA may be difficult to remove from columns once introduced therefore if TEA is to be used with a column, the column should be dedicated to methods with TEA.
The same research has shown though that TEA can be used to obtain advantageous changes in chromatography in under certain conditions. Data has demonstrated improved peak shape and selectivity for simple sugars when using TEA with Cogent columns. This effect is thought to be due at least partly to an ion-pairing mechanism of the TEA on the surface of the material. With ammonium acetate, a near-neutral pH is obtained with this additive, so it is a popular choice for keeping most organic acids ionized, which is generally preferred for ANP methods. In addition, it is LC-MS compatible, in contrast to a near neutral pH phosphate buffer.