Search

The method of detecting trace 1,4-dioxane in water using membrane extraction coupled with gas chromatography/differential mobility spectrometry (GC/DMS) was developed. The parameters including radio frequency voltage, sampling flow rate, permeation time and trapping time were optimized to 1000 V, 50 mL/min, 30 min and 150 s, respectively. The linear range for dioxane was obtained from 2.0 μg/L to 20.0 μg/L. The LOD was found to be 0. 67 μg/L. The specificity towards 1,4-dioxane in the presence of five chlorinated hydrocarbons was improved by using two-dimensional GC separation with optimized DMS compensation voltage. This method paves a way for developing field-deployable sensors for real-time monitoring contaminants in groundwater.

A nano-electrospray ionization-ion mobility spectrometer (nanoESI-IMS) was built up. Firstly, the effects of the parameters such as drift gas flow rate and solvent flow rate on the desolvation capability were studied and optimized. Then, a series of compounds were used to characterize the nanoESI-IMS system. The results showed that, complete desolvation was achieved for nano-electrospray ion droplets with the nanoESI-IMS apparatus. The limit of detection of this instrument for trioctylamine could reach 10 microg/L. Finally, this instrument was coupled to the high performance liquid chromatography (HPLC) as a detector for amines analysis. A test mixture containing triethylamine, diethylamine and butylamine was successfully separated and determined by the HPLC-nanoESI-IMS system. Linear response ranges of about two orders of magnitude were achieved for triethylamine, diethylamine and butylamine with this system.