Highly Selective Direct Determination of Sunset Yellow Using a Novel Polymeric Membrane Sensor Containing Metal Organic Framework Material

In this study, a novel polymeric membrane potentiometric sensor based on metal organic framework was presented for the direct determination of sunset yellow. The sensor was fabricated using different ratios of sensor components containing metal organic framework (MIL-101), polyvinylchloride, nitrophenyloctylether, bis-2-ethylhegzylsebecate, dibutylphthalate, and potassiumtetrakischlorophenylborate. The sensor components were optimized to obtain the best potentiometric response and the most desired response characteristics were achieved with the sensor composition including 6.0% ionophore (MIL-101), 26.0% polyvinylchloride, 67.0% dibutylphthalate and 1.0% potassiumtetra-p-chloro-phenylborate. The optimized sensor showed a linear response to sunset yellow over the concentration range of 1.0×10-6 ˗ 1.0×10-1 molL-1 (R2=0.9993) with a Nernstian slope of 35.7±0.5 mV/decade and the detection limit was calculated as 1.7×10-7 molL-1. The sensor response was highly repeatable, and its response time was measured as 5s on average. The sensor’s potential response was not affected by the change of hydronium ions in the solution between pH=5.40-9.55 and its lifetime was evaluated as 14 weeks. The sensor was used as an indicator electrode in the titration of sunset yellow with silver nitrate solution. Additionally, the usefulness for the analytical applications of the sensor were tested using the sunset yellow spiked different water samples and some pharmaceutical drug formulations.