SummaryA post-column chemiluminescent technique for the detection of compounds that are poor chromophores using electrogenerated chemiluminescence following separation by capillary electrophoresis is described. The luminescent signal is generated following the reaction of analytes (e.g. amines) with Ru(bpy)s3+, which is electrochemically generated post-column from Ru(hpyh2+. Tripropylamine and proline are used as two model compounds to demonstrate the feasibility of the method. Detection limits for the prototype system were in the micromolar range, suggesting that this technique offers an alternative to indirect detection of compounds that are poor chromophores with an added selectivity advantage. The system includes the use of a conductive joint to isolate the separation field from the potential necessary to drive the electrogenerated chemiluminescent reaction. Addition of the chemiluminescent reagent Ru(hpy)?+ post-column did not decrease the efficiency of the separation. The design and fabrication of the novel cell is discussed.

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SummaryDespite the impressive Jimits of detection and inherent seJectivily afforded by peroxyoxaJate chemiluminescence (POCL) detection, efficient coupling of POCL to capillary electrophoresis (CE) remains limited by the relatively slow kinetics of the reactions that drive imidazole-catalyzed chemiluminescence. Moreover, oxalate esters, usecl in POCL, are sparingly soluble in polar solvents ancl hydrolyze rapidly, presenting an additional challenge with respect to detection following aqueous phase separations. In this paper, a novel method forcouphng an ultrafast POCL reaction to CE is presented. Post separation electrokinetic delivery of the POCL reagent bis(2,4,6-trichlorophenyl)oxalate (TCPO) was accomplished using a commercially available micro tee. Electrokinetic addition of TCPO allowed for precise control of the ratio of TCPO to the chemiluminescence (CL) reagents 1,2,2,6,6-pentamethylpiperidine (PMP) ancl 1,2,4-triazole (triazole), spiked into the running buffer. This novel method for CL reagent delivery avoided the problems ancl costs associated with using pressure or mechanical pumps to deliver reagents post separation. Use of this dual-component system (PMPand triazole) resulted in intense CL with half-lives of less than 2 seconds. Optimum conditions for CE-POCL detection were investigated using stopped-flow kinetics. The detection limit for 3-aminofluoranthene, following separation byCE, was <0.95 nM.

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