Toluene Enhanced-High Pressure Photoionization-Time-of-Flight Mass Spectrometry for Highly Sensitive and Rapid Detection of Phenolic Compounds

Phenolic compounds are toxic and difficult to be degraded, and can cause serious pollution to the environment. Conventional off-line detection methods for phenolic compounds mostly require complicated and time-consuming pretreatment process. Therefore, it is an urgent need to develop a method for highly sensitive and rapid measurement of phenolic compounds. In this work, a novel toluene enhanced-high pressure photoionization (TE-HPPI) source, based on a vacuum ultraviolet (VUV) lamp filling with krypton (Kr) gas, was developed for rapid detection of phenolic compounds by time-of-flight mass spectrometry (TOFMS). By introducing toluene as the reagent molecule and elevating the ion source pressure, the detection sensitivities for 0. 5 mu g/L phenol, 3 -methylphenol, 2-chlorophenol, 2, 4-dichlorophenol and 2, 4, 6-trichloropenol were improved by 14.8, 2.68, 2.47, 2.33 and 2.30 times, respectively. The ionization process of phenolic compounds was not affected by sample humidity. A dynamic bubbling and purging inlet method was employed to measure phenolic compounds in liquid samples without any pretreatment process. The limits of detection ( LODs ) of phenol, 3-methylphenol, 2-chlorophenol, 2, 4-dichlorophenol and 2, 4, 6-trichloropenol in gas phase within 1 min were down to 0.24, 1.43, 0.42, 19.8 and 29.1 ng/L, respectively, while the LODs were 4.87, 3.60, 0.21, 1.50 and 4.32 mu g/L in solution, respectively. The method was successfully applied 14 analyzing phenolic compounds in sludge suspension from sewage treatment plants. The capability of high sensitivity, fast analysis, few fragmentation and simple spectrum interpretation have made the TE-HPPI-TOFMS as a promising tool in rapid detection and online monitoring of phenolic pollutants.