Developing potentiometric chemical sensors for sulfate determination is a rather challenging task due to a considerable hydrophilicity of this anion and its poor affinity to lipophilic plasticized polymeric membranes – one of the most popular sensor membrane materials nowadays. Not too many research works were devoted to this problem in the last years. Here we report on the successful development of several novel sulfate ionophores based on the synthetic modification of the commercially available sulfate ionophore I. The newly developed sensors outperform commercial analogue in terms of elelctrochemical sensitivity and selectivity. We have highlighted certain problems with numerical selectivity assessment in case when primary and interfering ions have different charges. The counterintuitive results yielded by conventional selectivity quantification methods implies the relevance of using alternative approach – visualizing sensor response curves towards primary ion in the presence of interfering ions. Novel sulfate sensors were applied for direct potentiometric measurements of sulfate content in river water samples demonstrating real applicability of the developed sensor membranes. © 2024 Elsevier B.V.