Impact of molecular structure and plasticization of PVC membranes in the response of solid-state ion-selective electrodes

• High MW PVC with a linear plasticizer offers stable, durable sensors with lower LOD. • High Tg values in PVC membranes do not always enhance sensor detection capabilities. • PVC membranes with 75 wt% of any plasticizer show optimal viscoelastic behavior. • SEM micrographs show small, homogeneous PVC aggregates boost sensor performance. Potentiometric sensors are essential in various industries due to their high sensitivity, simplicity, and cost-effectiveness. However, enhancing sensitivity, largely dependent on membrane diffusion, remains challenging. This study investigates the role of polyvinyl chloride (PVC) molecular weight and plasticizer type on optimizing potentiometric sensor performance for tartaric acid detection. Two PVCs with different molecular weights (HIGH and LOW) and distinct plasticizers were evaluated. Results demonstrated that membranes plasticized with dibutyl sebacate, a linear plasticizer, exhibited high sensitivity (0.0239 mV/pX) and repeatability, achieving a lower limit of detection (LOD = 4.31 × 10⁻⁵ M) compared to those with a bulky plasticizer. Specifically, HIGH PVC combined with a linear plasticizer provided saturation-free measurements, ensuring greater accuracy in tartaric acid quantification. This research underscores the impact of plasticizer selection on sensor optimization, enhancing accuracy and reliability in food quality control. By establishing the relationship between PVC structure and plasticizer type, this study contributes to advancing sensor technology for improved food safety and quality assessment.