Application of all solid-state 3D printed pH sensor to beverage samples using matrix matched standard

In this work, an all solid-state potentiometric pH sensor is developed, which employs a thin-film sputter deposited RuO₂ working electrode, a polyvinylbutyral-SiO₂ modified RuO₂ reference electrode and 3D printed electrode housing. The developed sensor exhibits linear pH response (- 55.7 mV/pH, R² = 0.9997) and reasonable reproducibility (hysteresis < 2 mV). Experimental results show that by using a previously developed sample-equilibration and single-point calibration protocol, an accuracy of ± 0.2 pH is achieved in a variety of sample matrices. However, by employing a matrix matched standard, bias errors are reduced and accuracy is improved to ± 0.1 pH, when compared to a commercial glass pH sensor. The developed sensor and measurement protocol is then rationalised for low throughput analysis by unskilled users.