pH polymeric membrane microelectrodes based on neutral carriers and their application in aquatic environments Original Research Article

pH polymeric membrane microelectrodes based on neutral carriers have been developed for sediment and bio-mat applications. The pH microelectrodes have a tip diameter of 10–40 μm and contain poly(vinyl chloride) (PVC) or carboxylated PVC in its membrane phase. Compared to classic liquid membrane pH microelectrodes without polymers, the new pH microelectrodes have a much longer lifetime (>1 month), a stronger tip, a lower resistance (1–4 × 109 Ω) and a shorter response time (t98 < 4 s). Most pH microelectrodes have been developed for physiological application, but this new one has been developed for application in harsh environments, such as sediments and microbial mats. Successful measurements of pH profiles in sediments and in microbial mats have been made with the new pH microelectrodes. The pH microelectrodes may also be applicable for clinical measurements and they require only a very small volume of the sample.