title: Dual detection of nitrate and mercury in water using disposable electrochemical sensors.
abstract: Here we report a disposable, cost effective electrochemical paper-based sensor for the detection of both nitrate and mercury ions in lake water and contaminated agricultural runoff. Disposable carbon paper electrodes were functionalized with selenium particles (SePs) and gold nanoparticles (AuNPs). The AuNPs served as a catalyst for the reduction of nitrate ions using differential pulse voltammetry techniques. The AuNPs also served as a nucleation sites for mercury ions. The SePs further reinforced this mercury ion nucleation due to their high binding affinity to mercury. Differential pulse stripping voltammetry techniques were used to further enhance mercury ion accumulation on the modified electrode. The fabricated electrode was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electrochemistry techniques. The obtained results show that the PEG-SH/SePs/AuNPs modified carbon paper electrode has a dual functionality in that it can detect both nitrate and mercury ions without any interference. The modified carbon paper electrode has improved the analytical sensitivity of nitrate and mercury ions with limits of detection of 8.6µM and 1.0ppb, respectively. Finally, the modified electrode was used to measure nitrate and mercury in lake water samples.
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, Saint Paul, MN 55108, United States.
authors.forename: Minh-Phuong N
authors.initials: MN
authors.lastname: Bui
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, Saint Paul, MN 55108, United States.
authors.forename: John
authors.initials: J
authors.lastname: Brockgreitens
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, Saint Paul, MN 55108, United States.
authors.forename: Snober
authors.initials: S
authors.lastname: Ahmed
authors.affiliation: Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, Saint Paul, MN 55108, United States. Electronic address: aabbas@umn.edu.
authors.forename: Abdennour
authors.initials: A
authors.lastname: Abbas
mesh_terms: D002244:Carbon / Q000737:chemistry; D055664:Electrochemical Techniques / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004784:Environmental Monitoring / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005618:Fresh Water; D006046:Gold / Q000737:chemistry; D060106:Lakes / Q000032:analysis*; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D009566:Nitrates / Q000032:analysis*; D011092:Polyethylene Glycols / Q000737:chemistry; D012643:Selenium / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009566:Nitrates; D013438:Sulfhydryl Compounds; D014874:Water Pollutants, Chemical; D011092:Polyethylene Glycols; D002244:Carbon; D006046:Gold; D008628:Mercury; D012643:Selenium
keywords: Disposable electrodes; Electrochemical sensors; Gold nanoparticles; Mercury detection; Nitrate detection; Selenium nanoparticles