extraction and identification of tnt explosive compound by dispersive liquid-liquid microextraction combined with silica aerogel thin film followed by thermal desorption unit-ion mobility spectrometry

Silica aerogel thin film prior to dispersive liquid-liquid microextraction method was applied for extracting and preconcentrating of trinitrotoluene (tnt) explosive compound. to evaporate and detection of the extracted tnt obtained by proposed method, ion mobility spectrometer equipped with thermal desorption unit was used. electrospinning procedure was done for preparing of the thin film. different effective parameters including extraction solvent, disperser solvent, centrifugation time, and evaporation time from thin film were optimized to increase the trace concentration of the tnt and the cleaning-up. under the optimized conditions, the calibration curve was plotted by least square method and the linear dynamic range (ldr) as well as correlation coefficient were obtained 10-200 µg l-1 and 0.9970, respectively. according to the signal to noise ratio (s/n) 3 and 10, the limit of detection (lod) and limit of quantification (loq) were calculated to be 3 µg l-1 and 10 µg l-1, respectively. to investigate the repeatability of the proposed method, the relative standard deviation (rsd) was calculated 2% for the tnt concentration of 50 µg l-1. to assess the ability of the method for extraction and identification of the analyte in the real sample, agricultural wastewater was used and the relative recovery value was obtained to be 114%.