Development of a metal/chelate polyhydroxyethylmethacrylate monolith capillary for selective depletion of immunoglobulin G from human plasma for proteomics

- Diethylene glycol diacrylate as crosslinker enhanced monolith mechanical strength.
- First report of IDA immobilization on aldehyde stationary phase i.e. monolith.
- Spacer arm did not enhance protein adsorption capacity of monoliths.
- Selective IgG (∼95%) adsorption in presence of other high abundant proteins.

In this study, we report the development of a new poly HEMA (HEMA-co-DEGDA-co-DATD) monolith capillary functionalized with “IDA-Cu (II) complex”. Of the two tested crosslinkers (methylene bisacrylamide (MBAAm) and diethylene glycol diacrylate (DEGDA)), presence of DEGDA has enhanced the monolith rigidity. Structural assembly of these monoliths are organized with highly interconnected large globule like structures and dominated by macropore region. Iminodiacetic acid (IDA) immobilization was performed using two chemical approaches (i. aldehyde − secondary amine reaction and ii. epoxy − sec. amine reaction). FT-IR analysis confirmed successful IDA immobilization in both cases. For the first time, a reaction of sec. amine ligand with aldehyde functional material was successfully reported. Overall, the Cu (II)-IDA monolith capillary showed good permeability (3.05 × 10 −13 m2), high IgG adsorption capacity and reusablilty even after 5 consecutive adsorption-desorption cycles. The amount of protein (IgG/HSA) adsorbed on Cu (II)-IDA monolith prepared via the two chemistries is almost similar. Using this affinity monolith capillary, we selectively depleted ∼95% of IgG from human plasma (dilution of 1:16).