Hi José,

the answer depends on your definition of best. Best can be in terms simplicity, accuracy, precision, cost, time for analysis, volume of sample required, gases to be analysed, susceptibility to interference, acceptance in scientific community etc. Can you share your requirements please?

For small scale reactors, I used wet gas meter for gas volume (or gas production) and GC equipped with TCD for gas composition (CH4, CO2, N2). When H2 and CO were target, we used trace gas GC.

Hi,

as Robert Thomas Bachmann already said, the answer can be very different. GC is probably the best way to do this measurements, but if your volume sample is large enough (around 3-400 mL), you may think to use a portable IR gas analyzer, that can give you percentages of methane, oxygen, CO2 , H2S.

Thank you Robert Thomas Bachmann

Thank Weimin Wu . This is the case of my study, smalls reactors, I will search for studies that used this method.

May be the Gas Chromatograph method is the best solution.