Institute for Plant Biology and Microbiology, University of Zčrich, Zollikerstrasse 107, CH-8008 Zčrich, Switzerland and (*) Department of Chemistry, Sam Houston State University, Huntsville, Texas USA
A gas chromatographic method is presented which distinguishes phosphine from hydrogen sulfide and other possible headspace gases of anaerobic microbial cultures. In anaerobic cultures spiked with phosphine, this gas is recovered in the liquid and gas phase down to 10 picograms per milliliter of gas or liquid. No biogenically produced phosphine was found. Phosphine in amounts as small as 30 nanograms per liter can be stored for several days in glass bottles covered with rubber septa, filled with nitrogen, in the presence or absence of water or of an anaerobic bacterial culture. Due to the selectivity of the detector and the retention characteristics of the porous layer open tubular polymer column alkanes, alkenes, and organosulfur compounds routinely found in anaerobic bacterial headspaces do not interfere with the analytical quantification of phosphine.