Letsoalo Mokgehle R, Ambushe Abayneh A, Mamo Messai A
Department of Chemical Sciences, Faculty of Science, University of Johannesburg, Auckland Park Campus, P. O. Box 17011, Johannesburg 2028, South Africa.
Department of Chemical Science, Faculty of Science, University of Johannesburg, Doornfontein Campus, P. O. Box 17011, Johannesburg 2028, South Africa.
ACS Omega. 2021 Nov 16;6(47):31528-31538. doi: 10.1021/acsomega.1c03955. eCollection 2021 Nov 30.
This study presents novel chemoresistive reduced graphene oxide-ion-imprinted polymer (IIP-rGO)-based sensors for detection of lead (Pb) ions. The ion-imprinted polymer was synthesized by bulk polymerization and modified with a variable amount of rGO incorporated to form an IIP-rGO composite. The amount of rGO in the polymer matrix affected the sensor's relative response, and 1:3 mass ratio produced excellent results, with a consistent trend as the concentration of Pb ions increased in the solution. The decrease in relative resistance (Δ/ ) followed an exponential decay relationship between the Δ/ response and the concentration of Pb ions in aqueous solutions. After solving the exponential decay function, it is observed that the sensor has the upper limit of Δ/ >1.7287 μg L, and the limit of detection of the sensor is 1.77 μg L. A nonimprinted polymer (NIP)-based sensor responded with a low relative resistance of the same magnitude although the concentration was varied. The response ratio of the IIP-based sensor to the NIP-based sensor (Δ/ )/(Δ/ ) as a function of the concentration of Pb ions in the solution shows that the response ratios recorded a maximum of around 22 at 50 μg L and then decreased as the concentration increased, following an exponential decay function with the minimum ratio of 2.09 at 200 μg L but never read 1. The sensor showed excellent selectivity against the bivalent cations Mn, Fe, Sn, and Ti. The sensor was capable of exhibiting 90% Δ/ response repeatability in a consecutive test.
本研究提出了一种基于化学电阻型还原氧化石墨烯-离子印迹聚合物（IIP-rGO）的新型传感器，用于检测铅（Pb）离子。离子印迹聚合物通过本体聚合法合成，并用不同量的rGO进行改性，以形成IIP-rGO复合材料。聚合物基质中rGO的量会影响传感器的相对响应，质量比为1:3时产生了优异的结果，随着溶液中Pb离子浓度的增加呈现出一致的趋势。相对电阻的下降（Δ/R）与水溶液中Pb离子浓度之间遵循指数衰减关系。求解指数衰减函数后发现，该传感器的Δ/R上限为>1.7287 μg/L，检测限为1.77 μg/L。基于非印迹聚合物（NIP）的传感器，尽管浓度变化，但相对电阻响应较低且幅度相同。基于IIP的传感器与基于NIP的传感器的响应比（Δ/R）IIP/（Δ/R）NIP作为溶液中Pb离子浓度的函数表明，响应比在50 μg/L时最高约为22，然后随着浓度增加而下降，遵循指数衰减函数，在200 μg/L时最小比为2.09，但从未达到1。该传感器对二价阳离子Mn、Fe、Sn和Ti表现出优异的选择性。在连续测试中，该传感器能够表现出90%的Δ/R响应重复性。
