Determination of Phenols in Groundwater by Solid-Phase Membrane Extraction Combined with Ultrasonic Derivatization-negative Chemical Ionization Mass Spectrometry

Due to their strong polarity, phenolic compounds cannot be directly determined by Gas Chromatography-Mass Spectrometry. Derivatization can reduce the strength of the polarity of phenols, and improve the detection sensitivity. However, the traditional derivative steps are tedious, with many interference factors and complex operations. By applying improvements to the traditional pretreatment method, phenols in groundwater were measured through solid-phase membrane extraction combined with Ultrasonic Derivatization-Negative Chemical Ionization Mass Spectrometry. The membrane was transferred into a derivative bottle after extraction, and then the elution and derivatization were processed simultaneously using ultrasound. The solution was determined by Gas Chromatography-Negative Chemical Ionization Mass Spectrometry directly. By determining the spiked samples at different concentration levels, the recoveries of the method for target components are in the range of 70%-90%, the detection limits are 0.25-0.35 μg/L and relative standard deviations (RSD) are less than 10%. The proposed method simplifies the traditional tedious steps by using 2 mL acetone for elution and derivation. All target objectives have good recoveries. Due to conducting the elution and derivation processes in an airtight environment, less interference factors were introduced without the problem of secondary pollution, and consequently the data were more reliable.