Planar micro flame ionization detector with minimized leak current

The flame ionization detector (FID) is the preferred method of hydrocarbon detection. Unfortunately, it is operated at high fuel and oxidant gas flow and therefore not suitable for portable applications. This work presents an FID miniaturized by means of MEMS technology (muFID) to reduce gas consumption. A former low-flow muFID suffers from a considerable leak current in spite of an integrated guard electrode. The current muFID with improved guard electrode successfully minimizes the leak current, such that the minimum detectable limit (MDL) only depends on sensitivity and noise. Both are evaluated and yield an MDL of 1.2middot10^-9 gC/s, which is a factor 20 above what can be expected from conventional FIDs.