The detectionandmeasurementoflowconcentrationsofarsenic(V)arethesubjectsofintenseresearch interestinchemistryandenvironmentalactivity.Inthisresearch,apolypyrrole-chitosan/cobaltferrite nanoparticles compositelayerwaspreparedusinganelectrodepositionmethodonagold-coatedglass slide. Thecompositelayerwascharacterizedusing field emissionscanningelectronmicroscopy,energy- dispersed spectroscopy,atomicforcemicroscopy,andahighsurfacestylusprofilometer.Thecomposite layerwasusedtodetectthearsenicinwater,andthesensorlimitationwasabout0.001ppm.The composite layerwastestedusingatomic-forcemicroscopybeforeandafterthedetectionofarsenic.Asa result, theroughnesswasdisoriented,asthearsenicwasboundonthesurfaceofthecompositelayer.