建立了基于COF@CNTs/Bi修饰玻碳电极的电化学法测定水中痕量Pb²⁺和Cd²⁺的方法。称取单壁碳纳米管（CNTs）0.1 g，加入25 mL二甲基亚砜，超声10 min；再加入对苯二甲酸二醛0.02 g和1，3，5-三（4-氨基苯基）苯0.035 g，超声5 min；接着加入2 mL 12 mol·L^-1乙酸溶液，超声10 min。用10 mL N，N-二甲基甲酰胺和10 mL无水乙醇重复洗涤3次，干燥，得到COF@CNTs。称取1 mg COF@CNTs，加入5 mL N，N-二甲基甲酰胺，超声5 min，得到悬浮液。移取5 μL悬浮液，滴涂在活化好的玻碳电极表面，得到COF@CNTs工作电极。以COF@CNTs为工作电极，Ag/AgCl为参比电极，铂丝为辅助电极，将该三电极系统置于Bi³⁺、Pb²⁺、Cd²⁺的标准溶液中，于-1.4 V下富集Bi³⁺、Pb²⁺、Cd²⁺ 360 s，得到COF@CNTs/Bi电极，再于-1.4~-0.2 V内进行扫描，记录Pb²⁺和Cd²⁺的溶出峰电流。结果显示，Pb²⁺和Cd²⁺的质量浓度在500 μg·L^-1以内与其对应的溶出峰电流呈线性关系，检出限（3S/N）均为0.33 μg·L^-1；基于COF@CNTs/Bi电极对100 μg·L^-1 Pb²⁺和Cd²⁺混合标准溶液平行测定5次，测定值的相对标准偏差（RSD）为3.9%；对自来水和湖水进行加标回收试验，Pb²⁺和Cd²⁺的回收率分别为96.2%~108%和95.3%~105%。

A method for the determination of trace Pb²⁺ and Cd²⁺ in water by electrochemical method based on glassy carbon electrode modified with COF@CNTs/Bi was established. Single-wall carbon nanotubes of 0.1 g was taken, dimethyl sulfoxide of 25 mL was added, and the mixture was treated for 10 min with ultrasonic. Dialdehyde terephthalate of 0.02 g and 1,3,5-tri(4-aminophenyl) benzene of 0.035 g were added for ultrasonic treatment of 5 min. Then 12 mol·L^-1 acetic acid solution of 2 mL was added for ultrasonic treatment of 10 min. After washing 3 times repeatedly with N,N-dimethylformamide of 10 mL and anhydrous ethanol of 10 mL and drying, COF@CNTs was obtained. N,N-dimethylformamide of 5 mL was added to COF@CNTs of 1 mg for ultrasonic treatment of 5 min to get the suspension. The suspension of 5 μL was dropped onto the activated glassy carbon electrode surface to obtain COF@CNTs working electrode. Using COF@CNTs as the working electrode, Ag/AgCl as the reference electrode and platinum wire as the auxiliary electrode, the three-electrode system was placed in standard solution of Bi³⁺, Pb²⁺ and Cd²⁺. Bi³⁺, Pb²⁺ and Cd²⁺ were enriched for 360 s at -1.4 V to prepare COF@CNTs/Bi electrode. The stripping peak currents of Pb²⁺ and Cd²⁺ were recorded in the range of -1.4--0.2 V. As shown by the results, linear relationships between values of mass concentration of Pb²⁺ and Cd²⁺ and their stripping peak current were kept within 500 μg·L^-1, with detection limits (3S/N) of 0.33 μg·L^-1. Pb²⁺ and Cd²⁺ mixed standard solution of 100 μg·L^-1 was determined 5 times in parallel based on COF@CNTs/Bi electrode, and RSDs of the determined values was 3.9%. Recovery test was made on tap water and lake water, giving results in the range of 96.2%-108% and 95.3%-105%, respectively.