When the oxygen scavenger was present, the charge measured in air closely matched those measured in the glove box for both lactate and creatinine in the 0.5 to 15 mM range. This demonstrates the potential for interference-free and calibration-free lactate and creatinine sensing in point-of-use applications even at low substrate concentrations. The possibility to use different reducing agents for AOx expands the potential for analyte diversification. Paraformaldehyde, used for glucose and lactate biosensors, is a practical choice for sensor fabrication and storage due to its solid form. For biosensors inhibited by paraformaldehyde, such as the creatinine biosensor, alternative reducing agents such as ethanol can be employed. This volatile alcohol can also be stabilized in a gelled form , releasing dissolved alcohol upon the addition of an aqueous sample.