Development and Application of a Method for the Analysis of Phenols by GC-ESI/MS
Date Issued
2014
Date
2014
Author(s)
Liao, Jhan-Hong
Abstract
Phenols are predominantly analyzed by liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS). The main problems encountered in LC/MS arise from coeluting matrix, which would affect the sensitivity of the analyte. On the other hand, better separation resolution could be achieved by GC/MS, but with low sensitivity due to heavy fragmentation under electron impact ionization (EI). In this work, we combined gas chromatography with electrospray ionization/mass spectrometry (GC-ESI/MS) in the analysis of phenols. In order to overcome peak tailing and obtain better resolution in GC, silylation of phenols was introduced. Because trimethylsilyl (TMS) derivatives of phenols hydrolyzed easily, electrospray droplets would chemically transform them into underivatized states. Sensitivity enhancement is expected, because phenolic groups are easily deprotonated under negative ion ESI.
The first part of this work was the analysis of phenols by GC-ESI/MS. Better separation resolution was achieved by silylation. Most TMS derivatives can be hydrolyzed by increasing the ratio of water in spray solvents. Among TMS derivatives of phenols, chlorophenols (CPs) showed the best hydrolysis efficiency. Due to partial hydrolysis, TMS derivatives of nitrophenols (NPs) could be detected in the forms of both underivatized NPs and TMS derivatives of NPs, providing evidence for qualitative analysis. The second part of this work was the optimization of the analysis of 19 CPs by GC-ESI/MS. The sensitivity of this method could be enhanced due to the characteristics of soft ionization of ESI/MS. For CPs standard solutions, the limits of detection (LODs) were in the range of 1 ppb to 1 ppt using selected ion monitoring (SIM) and/or multiple reaction monitoring (MRM) mode. The third part of this work was the analysis of CPs in soil by GC-ESI/MS. The problem caused by coeluting matrix could be overcome by the high separation resolution of GC. The complicated purification procedure of soil samples could be simplified. The LODs of this method were in the range of 1 ppb to 1 ppt for CPs in soil samples.
Subjects
氣相層析法
電灑法質譜
酚類
矽烷化
水解
土壤
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-R01223150-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):bbc51870583dda9c5e97ddd4bcb6d720