HPLC Method for Analysis of Isophthalic acid on Zodiac HST B Column

Isophthalic acid is an aromatic dicarboxylic acid with the chemical formula C₆H₄(CO₂H)₂. It appears as a colorless crystalline solid and is one of the three isomers of benzene dicarboxylic acid—the others being phthalic acid and terephthalic acid. In isophthalic acid, the two carboxyl groups (–COOH) are attached at the 1st and 3rd positions on the benzene ring, classifying it as the meta isomer.

Applications:

• Polyester Production: Primarily used in the synthesis of resins like polyethylene terephthalate (PET), essential for manufacturing plastic bottles and synthetic fibers.

• Coatings and Paints: An important component in the formulation of alkyd resins, which are used in paints and coatings for improved durability.

• Polyamide Resins & Epoxy Curing Agents: Enhances chemical resistance and structural integrity in various advanced polymer systems.

Analytical Method:

Isophthalic acid can be effectively retained, separated, and analyzed using the Zodiac HST B mixed-mode stationary phase column. The method utilizes a gradient elution with a simple mobile phase consisting of water, acetonitrile (MeCN), and phosphoric acid as a buffer. Detection is performed using UV at 210 nm, making this approach both efficient and versatile for the analysis of aromatic acids.