Department of Analytical Chemistry and Instrumental Analysis, Sciences Faculty, Autonoma University of Madrid, Avda. Francisco Tomas y Valiente, 7, E-28049, Madrid, Spain.
Mikrochim Acta. 2020 Mar 4;187(4):199. doi: 10.1007/s00604-020-4157-3.
Screen-printed carbon electrodes (SPCE) were modified with nanocomposite membranes based on polystyrene sulfonate (PSS) or poly(diallyldimethylammonium) (PDDA) matrices and different nanomaterials. Carbon nano-powders (CnP), carbon nano-fibers (CnF) and multi-walled carbon nano-tubes (MWCNTs) were incorporated on PSS matrix. Nickel was incorporated by ion exchange in PSS-CnP composite membranes. Gold nanoparticles (AuNp) were photochemically and electrochemically synthesised and introduced into PDDA membranes. The electrochemical behaviour of methylisothiazolinone (MIT) using these modified electrodes was studied by cyclic voltammetry in 0.1 mol L NaOH. No electrochemical response is obtained on PSS-nanocarbon transducers at the assayed conditions. The nickel-based transducers allow the MIT identification but not quantification. Using AuNp-based electrochemical transducers, it is observed that in presence of MIT, the electron transfer for AuNp reduction is inhibited, and an oxidation peak appears at + 0.45 V, indicating an interaction between MIT and AuNp on the electrode surface. These facts support the usefulness of the AuNp-based electrodes for the determination of MIT. The intensity of the anodic peak observed at + 0.45 V vs. Ag/AgCl was used as analytical signal for MIT determination. A linear relationship between anodic peak current and MIT concentration is observed in the range 8.7 to 36 mg L using the transducer prepared by incorporating gold into the PDDA membrane by ion exchange and synthesising AuNp electrochemically. For this electrode, the limit of detection is 2.6 mg L and the reproducibility, expressed as relative standard deviation (RSD), is lower than 7%. Graphical abstractSchematic representation of the preparation of gold nanoparticles (AuNp) and poly(diallyldimethylammonium) (PDDA)-based platforms and methylisothiazolinone (MIT) electrochemical response on these nanostructured platforms.
丝网印刷碳电极 (SPCE) 经过修饰，采用基于聚苯乙烯磺酸盐 (PSS) 或聚二烯丙基二甲基氯化铵 (PDDA) 基质和不同纳米材料的纳米复合膜。将碳纳米粉末 (CnP)、碳纳米纤维 (CnF) 和多壁碳纳米管 (MWCNTs) 掺入 PSS 基质中。通过离子交换将镍掺入 PSS-CnP 复合膜中。通过光化学和电化学合成金纳米粒子 (AuNp)，并将其引入 PDDA 膜中。使用这些修饰电极，通过循环伏安法在 0.1 mol L NaOH 中研究了甲基异噻唑啉酮 (MIT) 的电化学行为。在测定条件下，在 PSS-纳米碳换能器上没有得到电化学响应。基于镍的换能器允许鉴定 MIT，但不能定量。使用基于 AuNp 的电化学换能器，观察到在 MIT 存在下，AuNp 还原的电子转移被抑制，并且在 +0.45 V 处出现氧化峰，表明 MIT 和 AuNp 在电极表面相互作用。这些事实支持基于 AuNp 的电极用于测定 MIT。在 Au/AgCl 参比电极上观察到的+0.45 V 处的阳极峰强度用作 MIT 测定的分析信号。在使用通过离子交换将金掺入 PDDA 膜中并通过电化学合成 AuNp 制备的换能器中，观察到在 8.7 至 36 mg L 的范围内，阳极峰电流与 MIT 浓度之间存在线性关系。对于该电极，检测限为 2.6 mg L，相对标准偏差 (RSD) 表示的重现性低于 7%。
