Determination of 18 phenolic compounds in water by gas chromatography-tandem mass spectrometry coupled with solid phase extraction

Abstract

At present, the kinds and the hazards of phenolic compounds in water were unclear. Research aimed at methods for the simultaneous detection of multiple phenolic compounds is still in its nascent stages. It is necessary to establish a method for the simultaneous determination of phenolic compounds in water. An analytical method was developed for the simultaneous determination of the 18 phenolic compounds in water by gas chromatography-tandem mass spectrometry (GC-MS/MS) coupled with solid phase extraction (SPE). The phenolic compounds in water were enriched and separated on an SPE column. The optimal pretreatment method was established by optimizing the chromatographic and mass spectrometric conditions. The effects of the initial pH of the water sample, type of eluting solvent, and dosage of the washing solution were investigated. Then, the 18 phenolic compounds in the water samples were determined. The optimal pretreatment extraction conditions were determined to be as follows:final pH of water sample, 3.0; eluting solvent, ethyl acetate (10 mL); and elution rate, 1 mL/min. The phenolic compounds enriched and purified by SPE were finally determined by GC-MS/MS with an electrospray ionization (EI) source. The phenolic compounds were then quantitatively analyzed by the external standard method. The average recoveries of the 18 phenolic compounds were in the range of 51.7%-117.3% at four spiked levels, and the relative standard deviations (RSDs) were in the range of 3.1%-7.4%. The limits of detections (LODs) were 0.04-0.6 μg/L. Good linear relationships were observed for the phenolic compounds in their corresponding concentration ranges. The developed method was applied to determine the phenolic compounds in six kinds of water samples from rivers and lakes, domestic water, and process water. Fifteen of the phenolic compounds were detected, but 4-nonylphenol, 3-methyl-4-nitrophenol, and 2-methyl-4,6-dinitrophenol were not. Moreover, bisphenol A, 2,4,6-tribromophenol, and 2,4-dibromophnol had the highest contents of 49.4 μg/L. The contents and kinds of phenolic compounds in the rivers and lakes were highest. However, the contents of phenolic compounds in the domestic water were adverse compared with the rivers and lakes, in accord with National Standard GB 8537-2008. As opposed to traditional analytical methods, the present method is characterized by simple operation without derivative or the need for anhydrous sodium sulfate for water removal, as well as high sensitivity, good stability, and reliability. The establishment of this method has important theoretical and practical significance for the development of standards and for the control of residue phenolic residue levels in water.