Continuous-flow real-time and flow injection determination of rainwater pH with a poly(vinyl chloride)-based tubular membrane electrode

Improved Electrodeposited Iridium Oxide pH Sensor Fabricated on Etched Titanium Substrates

“…The detector responds to a certain property, for example, pH, that changes continuously as a result of the passage of the sample through the flow cell. pH sensors such as glass electrode, polymeric membrane electrodes, , stainless steel electrode, and ISFET, , were previously tested as detectors in pH flow injection systems. A recent literature survey indicated that none of the previously reported iridium oxide pH sensors were tested as a detector in pH FIA systems.…”

“…Distilled water is ideal in terms of its minimal effect on the sample pH. However, unstable baselines and noisy detector response are common problems, which limit the use of distilled water as a carrier stream. ,, Alternatively, buffered carrier streams provide stable baseline recordings. In this case, the effect of such buffered carrier streams on the pH values of injected samples must be minimized, because otherwise, the detector will respond to a different pH value that corresponds to the pH of the mixture of the sample and carrier stream.…”

Carrier-Based Ion-Selective Electrodes and Bulk Optodes. 2. Ionophores for Potentiometric and Optical Sensors

“…The pH being defined as the negative logarithm of the activity and not the concentration of H + , the activity of H + is for the vast majority of applications more relevant than its concentration. This can cause problems when samples of very low ionic strength, such as rainwater, are measured and ionic strength adjusters that affect the pH are used to allow for the simultaneous measurement of concentrations of other ions. , Of course, the same problem also occurs when activities of ions other than H + are of interest.…”

“…This can cause problems when samples of very low ionic strength, such as rainwater, are measured and ionic strength adjusters that affect the pH are used to allow for the simultaneous measurement of concentrations of other ions. 35,36 Of course, the same problem also occurs when activities of ions other than H + are of interest.…”

“…687 A recent reevaluation of the selectivity of Li + , Na + , Mg 2+ , and UO 2 2+ ionophores showed that the relatively similar UO 2 2+ ionophore UO 2 2+ -4 (ETH 295) gives a selectivity for Pb 2+ that is almost as good as that of ISEs based on Pb 2+ -1. Added ionic sites lead to a response slope of 35 Li + , -2.9; Cu 2+ , -3.9; Cd 2+ , -4.1; Ba 2+ , -2.4; Ag + , +0.1; oNPOE, KTpClPB; sample solution: nitrate salts, pH 4). 701 Furthermore, use of membranes containing added anionic sites and a 3,6-dioxaoctanedithioamide carrier (Pb 2+ -2, ETH 5435) resulted in Nernstian slopes typical for doubly charged Pb 2+ .…”