Dynamic versus static sampling for the quantitative analysis of volatile organic compounds in air with polydimethylsiloxane-carboxen solid-phase microextraction fibers.
Polydimethylsiloxane-Carboxen solid-phase microextraction fibers are now well known to be very efficient trapping media for the analysis of volatile organic compound (VOC) traces in air. However, competitive adsorption, due to the nature of the coating, considerably limits analyte quantitation. In this contribution, different experimental conditions are investigated to achieve quantitative analysis. Static and dynamic sampling were compared for the analysis of 11 VOCs in a standard gaseous mixture at different extraction times (1, 5, 15 and 45 min). The same experiments were performed with four isolated compounds. Adsorption results from gas mixture and isolated compounds were compared and a common linear range (i.e., where quantitative analysis is conceivable) was determined. When sampling was in the dynamic mode, compounds with lower affinity for the coating showed a very narrow linear range, meaning that competition for adsorption was quickly discriminative. The same experiments in static mode allowed one to obtain wider linear ranges for all compounds, especially for lower-affinity compounds: for a 1 min sampling time, acetone showed a linear adsorption range from 3 to 60 microg m(-3) in the dynamic mode which extended from 5 to 300 microg m(-3) in the static mode.
Tuduri
Ludovic
L
Laboratoire Génie de l'Environnement Industriel, Ecole des Mines d'Alès, France. ludovic.tuduri@ema.fr
Desauziers
Valérie
V
Fanlo
Jean Louis
JL
D000388:Air / Q000032:analysis*; D002138:Calibration; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D009930:Organic Chemicals / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012828:Silicones / Q000737:chemistry*; D014835:Volatilization
D004129:Dimethylpolysiloxanes; D009930:Organic Chemicals; D012828:Silicones; C013830:baysilon