Simple cryoconcentration technique for the determination of peroxyacyl and alkyl nitrates in the atmosphere

A gaseous mixture of methyl nitrate, n-propyl nitrate, peroxyacetyl nitrate and peroxypropionyl nitrate was successfully cryoconcentrated using a gas sampling valve with its loop filled with glass beads placed inside the GC oven which was cooled at -50 degrees C. The technique offered linearity over a ten fold concentration variation and sample volume range of 1-280 ml. The detection limit for 150 ml sample varied from 0.02-10 pptv depending on the compound.