Application of Convective Interaction Media (CIM) disk monolithic columns for fast separation and monitoring of organic acids.

The separation of organic acids on the anion-exchange monolithic support, commercially available as Convective Interaction Media (CIM), is presented in this study. It is demonstrated that citric, isocitric, pyruvic, fumaric, malic, and alpha-ketoglutaric acid can be successfully separated using a CIM monolithic column of suitable user-adjustable length. The effect of the mobile phase composition on the separation is investigated. CIM monolithic columns of adjustable length from 3 to 18 mm are compared regarding the resolution and the back pressure. It is shown that the CIM monolithic column of 12 mm in length enables a good separation of all six organic acids within 3 min and exhibits a linear dependence of back pressure versus flow rate. The resolution and the dynamic binding capacity are found to be flow-unaffected. A filtrated sample of bioprocess supernatant is analyzed without previous pretreatment, which indicates the possibility of online monitoring of small molecules during the bioprocess using CIM monolithic columns.