Dichlorodiphenyltrichloroethane determination in air by thermal desorption gas chromatography-mass spectrometry.

BACKGROUND: Current quantitative methods for airborne dichlorodiphenyltrichloroethane (DDT) require collection and extraction times of ≥ 12 h. The aim of this study was to develop a method for quantifying airborne DDT with a short (<4 h) collection and analysis time.

RESULTS: Precision [relative standard deviation (RSD)] for each calibration point (0.8-9.0), linearity (R(2) = 0.99) and apparent recovery (R' = 96.5%) were determined from thermal desorption (TD) gas chromatography-mass spectrometry (GC-MS) analyses of Tenax-TA-packed sampling tubes spiked with 1-250 ng of DDT. Recovery of (13) C-labeled 4,4'-DDT from tubes spiked before and after air sampling was 97.3 and 90.3% respectively. DDT was detected and quantified in 1-3 L samples of air collected during 10-180 min sampling events. A significant difference was observed in DDT air concentration between 28 and 33 °C during microchamber studies.

CONCLUSIONS: The results demonstrate that the TD GC-MS method developed in this study is precise, reproducible and linear over the span of 1-250 ng of DDT spiked onto TD tubes. By avoiding dilution of the sample, the method described allows the measurement of DDT vapor concentrations during short sampling periods (10-180 min) relevant to mosquito behavior studies.