关键词: 胶束反向扫集, 毛细管电泳, 量子点, 电化学发光, 胺

The strategy for electrochemiluminescence (ECL) sensor based on the CdSe quantum dots (QDs) to detect amines is proposed. We investigated the QDs ECL toward different amines, and found that amines could lead to the enhancement of ECL intensity. A novel amines detection platform based on micellar reversed sweeping, capillary electrophoresis (CE) separation, and quantum dots electrochemiluminescence detection was proposed for simultaneous detection of ractopamine and clenbuterol in meat samples. Firstly, the capillary was filled with running buffer containing SDS micelles. The electrophoretic velocity of SDS micelle was reverse to that of electroosmotic velocity. By controlling electroosmotic flow, the SDS-sample conjugates were at an immobile state in capillary. This immobile state was maintained for an extended period of time so that essentially unlimited volume of sample solution could be injected into the capillary. Then the sample was electrokinetically introduced into the separation capillary at 20 kV for 50 min. The negative charged SDS micelles in the buffer attracted the sample ions at the boundary of sample and buffer solution. The micellar reversed sweeping process allows introducing large amount of analytes into capillary to accumulate at the capillary inlet. After CE separation, the preconcentrated analytes sequentially enter into detection cell and lead to the enhancement of ECL intensity of QDs. The micellar reversed sweeping allows a large number of analytes trapped by SDS micelles, which could significantly amplify the QD's ECL signal for 6000-fold. The proposed method by micellar reversed sweeping and CE separation with QDs ECL detection realized the simultaneous and sensitive determination of ractopamine and clenbuterol in meat samples. The linear range were (0.8~2960) and (3.0~5520) μg/L and the limit of detection (LOD) were 96.8 and 192.5 ng/L for ractopamine and clenbuterol, respectively. CE based QDs ECL that combines the high separation efficiency of CE and the high sensitivity of QDs ECL has been proven to be a promising technique for amines compound assays.

Key words: micellar reversed sweeping, capillary electrophoresis, quantum dots, electrochemiluminescence, amines