RESUMO
A photo-cured membrane selective to calcium, based on the calcium bis [4-(1',1',3',3'-tetramethylbutyl)phenyl]phosphate ionophore and incorporating the lipophilic additive, potassium tetraki(4-chlorophenyl)borate, that can tolerate up to 200 nM perchlorate ionic background in the flow injection potentiometry mode has been previously reported (T. Dimitrakopoulos, J.R. Farrell and P.J. Ives, Electroanalysis, 8 (1996) 391). Improvements in the electrode slope and sensitivity of the previously described photo-cured calcium membrane-based electrode were achieved when anhydrous calcium chloride salt was dissolved into the pre-cured membrane composition and then photo-cured. Similar to the previously reported photo-cured calcium ion-selective electrode (ISE), the improved photo-cured calcium ISE can measure calcium in a high perchlorate background in the flow injection potentiometric mode.
RESUMO
There has been a rapid growth in the development of field-portable analytical instrumentation capable of in-situ and real-time feedback of data from remote sites. Advances have been made in applications for many technologies aided by developments in electronics, computing and telecommunications systems. This report presents a brief review of these developments and particularly of portable flow-injection systems applied in both the liquid and gas phase modes of operation with potentiometric sensors and gas sensors of the tin-oxide semiconductor types.
