Description General description Chromoionophore III (ETH 5350) is a pH sensitive dye, and is ratiometric that is the fluorescence spectrum has two peaks, and the ratio between these peaks changes according to the changing pH levels. Visit our Sensor Applications portal to learn more. Application ETH 5350 was used for the fabrication of optode membranes, which are sodium selective, used in order to optically determine sodium in pH-buffered human blood plasma. Assay of Na+ activity with solvent polymeric optode membrane prepared from ETH 5350 and sodium ionophore V; Assay of ammonia with solvent polymeric optode membranes based on ETH 5350 and valinomycin (potassium ionophore I) Packaging Bottomless glass bottle. Contents are inside inserted fused cone. Legal Information Selectophore is a trademark of Sigma-Aldrich Chemie GmbH