weak acid

 Step 5

We have established that your compound is a hydrophilic strong acid with one acidic group. Below is an example of a separation of a similar compound. This example can be used a starting condition in your method development.

Hydrophilic weak acids can be analyzed by any anion exchange Primesep column (Primesep D, B2). In strong acidic mobile phase (pH = 3 or below), carboxilic acids are not significantly ionized and molecules become more hydrophobic. Retention can be obtained with RP mechanism. At a higher pH the carboxylic acid becomes negatively charged and retention can be obtained due to IE interaction with the positively charged column. RP interaction still effects the retention and selectivity of separation.