Trace analysis of heavy metals in complex, environmentally relevant matrices remains a significant challenge for electrochemical sensors employing stripping voltammetry-based detection schemes. We present an alternative method capable of selectively preconcentrating Cu 2+ ions at the electrode surface using chelating polymer-wrapped multiwalled carbon nanotubes (MWCNTs). An electrochemical sensor consisting of poly-4vinyl pyridine (P4VP)-wrapped MWCNTs anchored to a poly(ethylene terephthalate) (PET)-modified gold electrode (r = 1.5 mm) was designed, produced, and evaluated. The P4VP is shown to form a strong association with Cu 2+ ions, permitting preconcentration adjacent to the electrode surface for interrogation via cyclic voltammetry. The sensor exhibited a detection limit of 0.5 ppm with a linear range of 1.1−13.8 ppm (16.6−216 μM) and a relative standard deviation (RSD) of 4.9% at the Environmental Protection Agency (EPA) limit of 1.3 ppm. Evaluation in tap water, lake water, ocean water, and deionized water rendered similar results, highlighting the generalizability of the presented preconcentration strategy. The advantages of electrochemical analysis paired with polymeric chelation represent an effective platform for the design and deployment of heavy metal sensors for continuous monitoring of natural waters.

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The mechanism of corrosion inhibition of zinc dithiomercaptothiadiazole (Zn(DMcT)2) has been known and elucidated. The efficacy of (Zn(DMcT)2) as used in primer coatings for corrosion inhibition on steel alloys such as 1010 steel and 4130 high strength steel under neutral pH conditions was investigated by accelerated corrosion testing methodologies. Solution-state studies and surface elemental analyses were conducted to determine the possible mechanism of corrosion inhibition. Solution state experiments showed a correlation between increasing Zn(DMcT)2 amounts and increased polarization resistance, but DMcT on its own did not show this relationship. Under neutral pH conditions, it was determined that Zn(II) species such as Zn(OH)2, Zn(DMcT)2, and possibly ZnO were deposited on the steel surface, providing corrosion protection.