A rapid, sensitive and real-time monitoring of alcohol content in spirit sample based on stable TiO2-coated porous silicon interferometer

A new real-time monitoring method for alcohol content in spirit samples has been established on base of stable TiO2-coated porous silicon (PSi) interferometer. There is a linear relationship between the different alcohol contents in range of 10%-70% (v/v) and efficient optical thickness (EOT) or the reflection peak positions of the sensing film. The alcohol content of sample can be measured by the EOT or the reflection peak positions with the TiO2 coated PSi interferometer. Both the straight TiO2-PSi and rugate TiO2-PSi can detect the alcohol contents, but the former displays a sensitivity of 2.911 nm +/- 0.145/alcohol content unit (ACU) which is fifty times more sensitive than that of the latter. The developed method is a rapid, sensitive, on-line, and cost-efficient detection technique without sample pretreatment for alcohol content in spirit samples. The results detected by the developed method for alcohol content in nine spirit samples are agreement with that of traditional alcoholmeter method. The novel established method has a great potential in food industry, environment and health fields for monitoring alcohol content.