how to obtain a concentration of 0.021 g CH4 per kg H2O given that it was prepared by a flow of 160 ml/min methane gas from methane cylinder into d H2O in an experiment on plants. but, i am going to transfer this methane in an air bag. and transfer methane gas from the methane filled air-bag using syringe. how much (v/v) of methane should i transfer to the broth culture to get the above mentioned concentration of methane. or another way how to get an equivalent amount( v/v) to that flow rate in my broth culture but from my air bag because it is difficult to bubble methane directly from the methane cylinder into my broth?