“…Organic nitrate quantification was accomplished through use of a Brucker Tensor FT-IR spectrometer (Brucker, Inc.). FT-IR has been successfully employed in several previous laboratory and field studies for organic nitrate quantification (Laurent and Allen, 2004;Dekermenjian et al, 1999;Noda et al, 2000;Hallquist et al, 1999;Nielsen et al, 1998). Filter and denuder extracts were analyzed in a 1 cm liquid cell and organic nitrate concentrations were determined using the asymmetric -NO 2 stretch at ∼ 1640 cm −1 , unique to organic nitrates (Nielsen et al, 1995).…”