Sensors based on synthesized SnO2 and In2O3 nanopowders showed high sensitivity to low concentrations of acetone in a humid environment which simulates human exhalation. 
SnO2
Sensors based on synthesized SnO2 and In2O3 nanopowders showed high sensitivity to low concentrations of acetone in a humid environment which simulates human exhalation.  In2O3-Au sensors have the maximum sensitivity at an operating temperature of 325 °C.  The In2O3-Au-sensors reliably record the change in acetone concentration in the concentration range from a minimum of 0.1 to 5 ppm with high accuracy, which is necessary for rapid diagnostics of the condition of patients with diabetes (1.8-5.0 ppm). 
In2O3
The addition of a small amount of AuIII ions to hydroxide sols significantly increases the threshold sensitivity and the sensor response in a wide range of acetone concentrations. 
AuIII