Simultaneous Detection Of O- , M- , P-Xylene By High-Field Asymmetric Waveform Ion Mobility Spectrometry

A novel simultaneous detection method for isomers by spectrometry feature acquisition-separation parameter optimization-isomer analysis was proposed and verified. Dependent on self-made UV-FAIMS instrument , we investigated the separation of o-, m-, p-xylene by high-field asymmetric waveform ion mobility spectrometry (FAIMS) . By analyzing the spectrometry feature of xylene isomers , the characteristic peaks of o-, m- and p-xylene were extracted; by analyzing the relationship between dispersion voltage and characteristic peak position, the best separation voltage range was determined to be 550-800 V, and by further analyzing of superimposing spectrometry , the best separation voltage was found to be 700 V under the carrier gas flow rate to be 400 L/h. Under this experimental condition, the peak positions of o-, m-, p-xylene characteristic ions were 4. 36 , 14. 96 and 11. 16 V , which kept a great spacing and maintained a fairly good one-to-one correspondence to xylene mixture detection spectrometry (Peak positions 4. 33 , 14. 71 and 11. 25 V) with errors of only 0.03 , 0. 25 and 0.09 V. The experiment realized the simultaneous separation and detection of the xylene mixture, and the result verified the correctness of the isomer detection method. Under the premise of retaining the characteristic peak , the detection limit of m-xylene was 0. 047 mg/m(3), which was less than the indoor air detection amount of 0. 20 mg/m(3) specified in the national standard GB/T 18883-2002, and the linear range was 0. 24-2. 4 mg/m(3). This study provided technical support 14 the detection of xylene isomers, and provided a methodological basis for the rapid and high-precision detection of isomers by UV-FAIMS.