New PVC Membrane-Based Ion-Selective Electrode for Ultrasensitive Detection of Bismuth(III) with Sudan I

Accurate and dependable measurement of bismuth is vital for ensuring the safety of drugs, managing industrial processes, and evaluating environmental pollution. In this study, a new potentiometric sensor that uses Sudan I as the electroactive material within poly(vinyl chloride) (PVC) membrane structure was designed. The sensor displayed a broad linear concentration range of 1.0 ×10-3 to 1.0 ×10-10 M, an ultra-low detection limit of 4.0 ×10-11 M, and a response time of 30 seconds. It retained stable performance across a pH range of 2.0–7.0 and had an operational lifetime of about one month. When compared to existing literature, the sensor's selectivity and detection limit were significantly enhanced. It was successfully utilized to determine bismuth species in pharmaceutical formulations. Potentiometric methods provide clear advantages over other analytical techniques, such as simplicity, cost-effectiveness, quick response, and high selectivity. This developed sensor is a valuable tool for bismuth(III) determination, especially in quality control and pharmaceutical analysis. © 2025, Chemical Society of Pakistan. All rights resevered.