Coupling trypsin enzyme onto chromatographic supports provides a platform to reuse the enzyme and automate the hydrolysis process. A monolithic chromatographic support, such as Convective Interaction Media (CIM®), enables mass transfer of molecules within its channels exclusively by convective flow. This results in enzymatic conversion which is not limited by diffusion, making CIM® monoliths ideal for the preparation of immobilised monolith enzymatic reactors (IMERs). BIA Separations offers CIMac™ trypsin IMER with a bed volume of 0.1 mL as analytical platform for mass spectrometry (MS)-based proteomics. Larger volume IMERs (up to 80 mL) are available for industrial scale production of protein hydrolysates. The following example describes the enzymatic production of β-Lactoglobulin (β-Lg) hydrolysates using monoliths with 2 μm (N1) or 6 μm (N2) average channel diameter.
The application describes separation of Ni species by assembling four weak CIM DEAE anion-exchange disks into a monolithic column. The concentrations of the Ni species eluted from the column were quantified by post-column isotope dilution inductively coupled plasma mass spectrometry (ID)-ICP-MS. The Ni binding ligands eluted under the chromatographic peaks were identified off-line by tandem electro spray mass spectrometry (ESI-MS-MS), scanning for negative ions.
The mild chromatographic conditions of the CIM DEAE disks preserved chemical species and enabled separation of negatively charged Ni complexes.4 NH4NO3 was chosen as eluent since it enabled separation of Ni species and is compatible with ICP-MS and mass spectrometry detectors.