Improper use and harmful effects of nitrite ions pose a significant risk to human health. To address this concern, the use of carbon-based materials for electrochemical sensing is regarded as one of the most promising detection tools for ensuring the quality of drinking water and food products. In this context, we developed laser-ablated graphene electrodes (LAGEs) by direct laser scribing on a polyimide substrate, which were subsequently modified by electrochemical deposition of a redox-active melanin-like film (MeLF/LAGEs). Electrochemical investigations showed that the polymeric film had a beneficial effect on the heterogeneous electron transfer rate and induced an increase in the electrochemically active surface area and charge capacitance of the modified electrodes owing to the newly added catechol and o-quinone moieties. Taking advantage of the redox activity of MeLF films, in-solution probe-free redox capacitance spectroscopy was used as a sensitive and highly adaptable method for sensing nitrite ions. Upon the interaction between the nitrite ions and the MeLF/LAGE redox interface, the charge distribution and its inherent redox capacitance were altered, which allowed the successful detection of nitrite ions with a detection limit of 2.45 μM (S/N = 3) and a wide dynamic range (10 μM to 10 mM). This sensor demonstrated high recovery rates when applied to tap and mineral water samples and five different processed meat samples, highlighting its potential for the routine detection of nitrite ions through scavenging.

中文翻译：

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用氧化还原黑色素类薄膜改性的激光烧蚀石墨烯电极，通过清除亚硝酸盐离子实现氧化还原电容传感


亚硝酸盐离子的使用不当和有害影响对人类健康构成重大风险。为了解决这一问题，使用碳基材料进行电化学传感被认为是确保饮用水和食品质量的最有前途的检测工具之一。在此背景下，我们通过在聚酰亚胺衬底上直接激光划线开发了激光烧蚀石墨烯电极 （LAGEs），随后通过氧化还原活性黑色素样膜 （MeLF/LAGEs） 的电化学沉积进行了改性。电化学研究表明，聚合物薄膜对异质电子转移速率有有益的影响，并且由于新添加的邻苯二酚和邻醌部分，诱导了改性电极的电化学活性表面积和电荷电容的增加。利用 MeLF 薄膜的氧化还原活性，溶液中无探针氧化还原电容光谱被用作传感亚硝酸盐离子的灵敏且适应性强的方法。亚硝酸盐离子与 MeLF/LAGE 氧化还原界面相互作用后，电荷分布及其固有的氧化还原电容发生变化，从而成功检测亚硝酸盐离子，检测限为 2.45 μM （S/N = 3），动态范围宽（10 μM 至 10 mM）。该传感器在应用于自来水和矿泉水样品以及五种不同的加工肉类样品时表现出高回收率，凸显了其通过清除进行亚硝酸盐离子常规检测的潜力。