Sensor based on β-NiOx hybrid film/multi-walled carbon nanotubes composite electrode for groundwater salinization inspection

摘要: Abstract The enrichment of groundwater with different nutrients (Na + , Ca 2+ Mg Cl − CO 3 2− among others) triggers the salinization aquifer and makes it inappropriate for many purposes. In this work, we developed a highly sensitive selective electrochemical sensor, based on Ni -inorganic films electrosynthetized in situ onto multi-walled carbon nanotubes composite paste electrode (MWCNE), which allows early detection salinization. working sensor ( β - NiO x /MWCNE) was derivatized from nickel hexacyanoferrate modified strong alkaline medium (pH = 12), producing hybrid film composed by OH ) 2 ). properties, morphology chemical composition formed thin were evaluated voltammetry, scanning electron microscopy X-ray spectroscopy. /MWCNE to presence Na cation ion-exchange, increase concentration range 4.46 × 10 −7 4.93 × 10 −6  mol L −1 inhibited linearly reversible signal device, allowing determine trace concentrations ion (LOD = 9.86 × 10 −8 high correlation coefficient data r  = 0.999) suitable precision/reproducibility measurements (RSD  as marker electroanalytical found evidences Grossos, Brazil coast city, whose inhabitants have hypertension above national average. attained results comparable those obtained standard methods analysis (percentage error ranging 0.5 1.6%), confirming accuracy proposed platform.