Novel polymer-modified electrodes for batch injection sensors and application to environmental analysis

Various polymer coatings have been investigated for the protection of mercu ry thin-film electrodes in the square wave anodic stripping voltammetry of environmental samples using batch injection analysis, with injection of unt reated samples of volume 50 mu l directly over the sensing electrode. Polym er coatings studied include those with controlled porosity, and cation-exch ange polymers based on sulphonated polymers. Of the polymers tested, films of ca. 1 mu m thickness made from Nafion(R) mixed with 5% poly(vinyl sulpho nic acid) were found to give the best results in tests with the model surfa ctants Triton-X-100 detergent, sodium dodecyl sulphate and protein standard . The validity of the approach is demonstrated by application to real sampl es. (C) 1999 Elsevier Science S.A. All rights reserved.