College of Chemistry and Chemical Engineering, Heze University , Heze, China.
College of Agricultural and Biological Engineering, Heze University , Heze, China.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2020 Sep;37(9):1459-1466. doi: 10.1080/19440049.2020.1769867. Epub 2020 Jul 3.
In this paper we report the modification with citrulline of the surface of a glassy carbon electrode (GCE) through cyclic voltammetry to prepare a polycitrulline-modified electrode (PCit/GCE). The electrochemical behaviour of ractopamine on this PCit/GCE was then investigated by cyclic voltammetry, to establish a novel electrochemical method for the detection of ractopamine residues in animal tissue. The optimum preparation conditions for the modified electrode were found to include a polymerisation solution pH of 6.8. The cyclic voltammetry required 12 scan cycles at a scan rate of 40 mV/s with a potential range of -1.6 to 2.3 V. The optimum conditions to determine ractopamine were in a solution of pH 6.0 with cyclic voltammetry performed at a scan rate of 60 mV/s and a potential range of 0.4 to 1.0 V. To analyse meat, the tissue sample was extracted with ethanol, filtered, evaporated to dryness and diluted with phosphate buffered saline at pH of 6.0 before being analysed in the electrochemical cell. The limit of detection of the new method for ractopamine was 1.0 ng/g and the correlation coefficient (R) was 0.9991 in the concentration range of 140-5410 ng/g. Ractopamine residue levels in spiked beef and mutton samples were detected by the modified electrode and the recovery was in the range of 96%-101%, giving results consistent with a validated HPLC method. This study provides a new method for detection and quantification of ractopamine residues in animal tissue.
本文通过循环伏安法在玻碳电极（GCE）表面修饰瓜氨酸，制备聚瓜氨酸修饰电极（PCit/GCE），报道了这一修饰方法。然后通过循环伏安法研究了莱克多巴胺在该 PCit/GCE 上的电化学行为，建立了一种检测动物组织中莱克多巴胺残留的新电化学方法。研究发现，修饰电极的最佳制备条件包括聚合溶液 pH 值为 6.8。循环伏安法需要在扫描速率为 40 mV/s、电位范围为-1.6 至 2.3 V 的条件下进行 12 个扫描循环。最佳的莱克多巴胺测定条件为 pH 6.0 的溶液，在扫描速率为 60 mV/s、电位范围为 0.4 至 1.0 V 的条件下进行循环伏安法。为了分析肉类，将组织样品用乙醇提取、过滤、蒸发至干燥，然后用 pH 为 6.0 的磷酸盐缓冲盐水稀释，再在电化学池中进行分析。该方法检测莱克多巴胺的检出限为 1.0 ng/g，在 140-5410 ng/g 的浓度范围内相关系数（R）为 0.9991。用修饰电极检测牛肉和羊肉样品中的莱克多巴胺残留，回收率在 96%-101%之间，与验证的 HPLC 方法的结果一致。本研究为检测和定量动物组织中莱克多巴胺残留提供了一种新方法。
