Fig. 1.
Chromatogram of the different classes of aldehydes measured in an induced sputum sample. Peak identification and analyte concentration: 1) malondialdehyde, 33.7 nM; 2) 4-hydroxyhexenal, 7.3 nM; 3) acrolein, 15.8 nM; 4) 4-hydroxynonenal, 7.9 nM; 5) n-hexanal, 14.9 nM; 6) n-heptanal, 15.6 nM; and 7) n-nonanal, 64.7 nM.