A miniaturized analysis system composed of monolith-based microchip electrochromatography coupled with on-line chemiluminescence detection for amino acids

• A miniaturized analysis system detection of unlabeled amino acids was proposed.
• Manipulation of fluid is realized by a simple and low-cost negative pressure device.
• It has the advantages of simplicity, sensitivity and superior separation performance.

Miniaturized chemical analysis instruments using micromachining techniques are receiving increasing attention. We presented a compact microchip-based electrochromatography (μCEC)-chemiluminescence (CL) system for the detection of amino acids. Monoliths prepared by in situ photopolymerization in the separation channel of the microchip served as the stationary phase of the μCEC coupled with CL detection. Negative pressure combined with electrokinetic force injection method was utilized for sampling and transporting CL reagents in this system. The amino acids were directly analyzed by enhanced Cu2+ catalyzed activity for luminol-hydrogen peroxide CL reaction as the formation of Cu2+-biomolecule complexes online. Glycine (Gly), Glutamic acid (Glu), Arginine (Arg) and Aspartic acid (Asp) were chosen as model compounds to evaluate the performance of the μCEC-CL system. The results demonstrated that the proposed system offered a number of benefits including miniaturization, significant simplification in operation and instrumentation; what is more, amino acids were directly analyzed without complex labeling procedure.

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