Moreira Roger Cardoso, Costa Brenda M C, Marra Mariana C, Santana Mario H P, Maldaner Adriano O, Botelho Élvio D, Paixão Thiago R L C, Richter Eduardo Mathias, Coltro Wendell K T
Instituto de Química, Universidade Federal de Goiás, Goiânia, GO, Brazil.
Instituto de Química, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
Electrophoresis. 2018 Sep;39(17):2188-2194. doi: 10.1002/elps.201800137. Epub 2018 Jul 17.
This study describes the development of a new analytical method for the separation and detection of cocaine (COC) and its adulterants, or cutting agents, using microchip electrophoresis (ME) devices coupled with capacitively coupled contactless conductivity detection (C D). All the experiments were carried out using a glass commercial ME device containing two pairs of integrated sensing electrodes. The running buffer composed of 20 mmol/L amino-2-(hydroxymethyl) propane-1,3-diol and 10 mmol/L 3,4-dimethoxycinnamic acid provided the best separation conditions for COC and its adulterants with baseline resolution (R > 1.6), separation efficiencies ranging from (2.9 ± 0.1) to (3.2 ± 0.2) × 10 plates/m, and estimated LOD values between 40 and 150 μmol/L. The quantification of COC was successfully performed in four samples seized by the Brazilian Federal Police Department and all predicted values agree with values estimated by the reference method. Some other interfering species were detected in the seized samples during the screening procedure on ME-C D devices. While lidocaine was detected in sample 3, the presence of levamisole was observed in samples 2 and 4. However, their concentrations were estimated to be below the LOQ. ME-C D devices have proved to be quite efficient for the identification and quantification of COC with errors lower than 10% when compared to the data obtained by a reference method. The approach herein reported offers great potential to be used for on-site COC screening in seized samples.
本研究描述了一种新的分析方法的开发，该方法使用微芯片电泳（ME）设备与电容耦合非接触式电导检测（CD）相结合，用于分离和检测可卡因（COC）及其掺杂物或切割剂。所有实验均使用包含两对集成传感电极的商用玻璃ME设备进行。由20 mmol/L氨基-2-（羟甲基）丙烷-1,3-二醇和10 mmol/L 3,4-二甲氧基肉桂酸组成的运行缓冲液为COC及其掺杂物提供了最佳分离条件，基线分辨率（R>1.6），分离效率范围为（2.9±0.1）至（3.2±0.2）×10块板/米，估计检测限（LOD）值在40至150μmol/L之间。在巴西联邦警察局查获的四个样品中成功进行了COC的定量分析，所有预测值与参考方法估计的值一致。在ME-CD设备的筛查过程中，在查获的样品中检测到了一些其他干扰物质。在样品3中检测到利多卡因，在样品2和4中观察到左旋咪唑的存在。然而，估计它们的浓度低于定量限（LOQ）。与参考方法获得的数据相比，ME-CD设备已被证明在识别和定量COC方面非常有效，误差低于10%。本文报道的方法在用于现场筛查查获样品中的COC方面具有巨大潜力。
