Breakthrough in pH Measurement: Chip-based Sensor with Enhanced Performance

Scientists at the Fraunhofer Institute for Photonic Microsystems (IPMS) have announced a significant advancement in pH measurement technology. They have successfully developed a novel pH sensing layer and integrated it into an ion-sensitive field-effect transistor (ISFET), paving the way for more compact, precise, and versatile pH sensors.

pH, or potential of hydrogen, is a crucial parameter in various fields, including chemical and biochemical analysis, environmental monitoring, and medical diagnostics. Traditional methods for pH measurement often rely on bulky glass electrodes, which can be fragile and limited in their applications. ISFETs offer a potential alternative, being miniaturized and solid-state devices. However, their performance has been hindered by limitations in the sensitivity and stability of their sensing layers.

The research team at Fraunhofer IPMS has addressed this challenge by creating a pioneering sensing layer that significantly improves the capabilities of ISFETs for pH measurement. This new layer is based on amphoteric metal oxide, a material that can reversibly bind to both hydrogen and hydroxide ions depending on the surrounding pH. When the ISFET comes into contact with a solution, these ions interact with the sensing layer, generating an electrical signal that corresponds to the solution's pH.

The novel ISFET sensor boasts several advantages over traditional methods and existing ISFET technology. It offers a wide measurement range, capable of detecting pH levels from 1 to 13. The sensor chip itself is compact, measuring only 5 x 5 millimeters, making it suitable for various applications where miniaturization is crucial, such as in portable devices and integrated microfluidic systems.

Furthermore, the new sensor demonstrates exceptional stability with minimal signal drift and low hysteresis, ensuring accurate and reliable measurements over time. Additionally, it exhibits significantly reduced light sensitivity, a common challenge faced by ISFETs, making it more robust in diverse environments.

One of the most significant benefits of the new ISFET sensor is its dry storage capability. Unlike traditional glass electrodes that require constant storage in a solution to maintain their functionality, the new sensor can be stored dry for extended periods, simplifying storage and transportation logistics.

This breakthrough in pH measurement technology has the potential to revolutionize various fields. The compact, precise, and user-friendly nature of the new ISFET sensor opens doors for its application in areas like environmental monitoring, industrial process control, and medical diagnostics. With its ability to measure pH in real-time and in-situ, the sensor could play a vital role in advancing research and development across various disciplines.