18.104.22.168. Fuel cell devices
From the different types of fuel cells, electro-galvanic lead-oxygen cells can be operated at room temperature (low temperature cells), while Zirconia cells require internal cell heating to high temperatures (> 500°C). Lead-oxygen cell devices (like the Oxzilla 2, Sable Systems; the S 104, Qubit Systems; etc.) are not extremely fast in reaction but appropriate for honey bee measurement and easy to handle. These cells are very sensitive to pressure differences between reference and measurement channel. Pressure sensitivity is an inevitable consequence of the fact that fuel cell devices do not measure O2 ‘concentration’ but O2 ‘partial pressure’. Therefore, a parallel measurement setup is of great benefit (see section 22.214.171.124.). Their high sensitivity to (partial) pressure changes is, on the other hand, the basis of their high sensitivity. The slower (but usually sufficient) reaction of low temperature fuel cells may (in part) be compensated mathematically (post-hoc) by a Z transformation ("instantaneous correction") if restoration of the original shape of a respiratory event is an important parameter in an experiment (Lighton, 2008). Zirconia cells react faster. Appropriate air drying is indispensable in all fuel cells to achieve the best results.