Codeine is a common analgesic drug that is a pro-drug of morphine. It also has a high risk of abuse as a recreational drug because of its extensive distribution as an OTC drug. Therefore, sensitive and selective screening methods for codeine are crucial in forensic analytical chemistry. To date, a commercial analytical kit has not been developed for dedicated codeine determination, and there is a need for an analytical method to quantify codeine in the field. In the present work, potential modulation was combined with electrochemiluminescence (ECL) for sensitive determination of codeine. The potential modulated technique involved applying a signal to electrodes by superimposing an AC potential on the DC potential. When tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy)₃]²⁺) was used as an ECL emitter, ECL activity was confirmed for codeine. A detailed investigation of the electrochemical reaction mechanism suggested a characteristic ECL reaction mechanism involving electrochemical oxidation of the opioid framework. Besides the usual ECL reaction derived from the amine framework, selective detection of codeine was possible under the measurement conditions, with clear luminescence observed in an acidic solution. The sensitivity of codeine detection by potential modulated-ECL was one order of magnitude higher than that obtained with the conventional potential sweep method. The proposed method was applied to codeine determination in actual prescription medications and OTC drug samples. Codeine was selectively determined from other compounds in medications and showed good linearity with a low detection limit (150 ng mL⁻¹).

可待因是一种常见的镇痛药，是吗啡的前体药物。由于它作为非处方药广泛分布，因此作为消遣性药物滥用的风险也很高。因此，可待因的灵敏和选择性筛选方法在法医分析化学中至关重要。迄今为止，尚未开发出用于专用可待因测定的商业分析试剂盒，并且需要一种分析方法来现场定量可待因。在目前的工作中，电位调制与电化学发光（ECL）相结合，用于可待因的灵敏测定。电势调制技术涉及通过将交流电势叠加在直流电势上来向电极施加信号。当三(2,2'-联吡啶)钌(II) ([Ru(bpy) ₃ ] ²⁺ )用作ECL发射体时，证实了可待因的ECL活性。对电化学反应机制的详细研究表明，ECL 反应机制涉及阿片类骨架的电化学氧化。除了源自胺骨架的常见 ECL 反应外，在测量条件下可以选择性检测可待因，在酸性溶液中观察到清晰的发光。电位调制 ECL 检测可待因的灵敏度比传统电位扫描方法高一个数量级。该方法适用于实际处方药和非处方药样品中可待因的测定。从药物中的其他化合物中选择性地测定可待因，并显示出良好的线性和低检测限（150 ng mL ^-1）。