Siebert_2023_Anal.Chim.Acta_1275_341566

Enzyme assays can be performed with the capillary electrophoresis technique (CE) in many approaches, such as the immobilized enzyme micro-reactor. Acetylcholinesterase is a promising enzyme to be used when pursuing such a method, as it has already been explored in the proposal of similar methods of miniaturizing enzyme assays. The present work proposes a novel enzyme micro-reactor, based on the anchorage of the enzyme on magnetic nanoparticles of MnFe(2)O(4,) with chitosan and glutaraldehyde as the cross-linker in the capillary by means of an arrange of neodymium magnets. The calculated K(m) of the enzyme evaluated by this method was 1.12 mmol L(-1), comparable to other studies in the literature that utilizes immobilized enzymes. Also, IC(50) for neostigmine was assessed in 3 different micro-reactors, with an average of 29.42 +/- 3.88 micromol L(-1). In terms of the micro-reactor stability, it was possible to perform at least 25 experiments with assembled micro-reactor. The method was applied to hydroalcoholic extracts of 7 plant species. Plinia cauliflora had the best result, with 42.31 +/- 6.81% of enzyme inhibition in a concentration of 100 mg L(-1).