The International Agency for Research cancer (IARC) has classified nitrite in Group 2A of probable carcinogens to human. Herein, we report on the rapid and selective colorimetric detection of nitrite using a chemically modified gold nanoparticle (AuNP)-cerium oxide (CeO₂) NP-anchored graphene oxide (GO) hybrid nanozyme in a catalytic colorimetric assay where nitrite acts as the main oxidant/target analyte and 3,3′,5,5′-tetramethylbenzidine (TMB) as the substrate. CeO₂ NPs and GO were synthesized separately and incorporated in-situ, in a synthetic solution involving the chemical reduction of Au salt to AuNPs. The chemical modification process aided the adsorption of CeO₂ NPs and AuNPs on GO nanosheets, yielding a highly catalytic AuNP–CeO₂ NP@GO nanohybrid material. Under optimum experimental conditions, a novel colorimetric assay for nitrite recognition was constructed in which AuNP–CeO₂ NP@GO hybrid nanozyme catalysed the oxidation of TMB in the presence of nitrite prepared in a 2-(n-morpholino)ethanesulfonic acid-2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)propane-1,3-diol-tris(hydroxymethyl)aminomethane acetate (MES-BIS-TRIS-Trisma Ac)-citric acid buffer solution, pH 2. Nitrite was quantitatively detected in a concentration dependent manner from 100 μM to 5000 μM with a correlation coefficient of 0.9961 and a limit of detection of 4.6 μM. Selective detection of nitrite was confirmed by the generation of a unique green colour reaction upon nitrite interaction in the AuNP–CeO₂ NP@GO hybrid nanozyme redox cycle with TMB. None of the several tested metal ions and including H₂O₂ yielded a positive colour response, thus demonstrating the superior selectivity of the catalytic colorimetric assay for nitrite recognition. The AuNP–CeO₂ NP@GO hybrid nanozyme catalytic colorimetric assay was successfully applied in the detection of nitrite in tap water.

国际癌症研究机构（IARC）已将亚硝酸盐分类为人类可能的致癌物2A组。在本文中，我们报告了在亚硝酸盐作为主要比色法的催化比色测定中，使用化学修饰的金纳米粒子（AuNP）-氧化铈（CeO ₂）NP-锚定氧化石墨烯（GO）杂合纳米酶进行快速，选择性比色检测的方法。氧化剂/目标分析物和3,3'，5,5'-四甲基联苯胺（TMB）作为底物。CeO ₂ NP和GO分别合成，并在涉及将Au盐化学还原成AuNPs的合成溶液中原位掺入。化学修饰过程有助于Ce纳米颗粒上的CeO ₂ NP和AuNPs的吸附，产生高催化性的AuNP–CeO _2。NP @ GO纳米杂化材料。在最佳实验条件下，构建了一种新的比色法用于亚硝酸盐识别，其中AuNP–CeO ₂ NP @ GO杂合纳米酶在2-（n-吗啉代）乙磺酸-2-制备的亚硝酸盐存在下催化TMB的氧化。 [双（2-羟乙基）氨基] -2-（羟甲基）丙烷-1,3-二醇-三（羟甲基）氨基甲烷乙酸盐（MES-BIS-TRIS-Trisma Ac）-柠檬酸缓冲溶液，pH2。亚硝酸盐为以100μM至5000μM的浓度依赖性方式定量检测，相关系数为0.9961，检出限为4.6μM。通过在AuNP–CeO _2中进行亚硝酸盐相互作用产生独特的绿色反应，可以确认亚硝酸盐的选择性检测具有TMB的NP @ GO杂合纳米酶氧化还原循环。几种测试的金属离子（包括H ₂ O _2）均未产生正色响应，因此证明了用于亚硝酸盐识别的催化比色测定具有优越的选择性。AuNP–CeO ₂ NP @ GO杂合纳米酶催化比色法已成功应用于自来水中亚硝酸盐的检测。