A traceless clean-up method coupled with gas chromatography and mass spectrometry for analyzing polycyclic aromatic hydrocarbons in complex plant leaf matrices

Analyst. 2020 May 7;145(9):3266-3273. doi: 10.1039/d0an00128g. Epub 2020 Apr 1.

Abstract

This study developed a traceless clean-up method by combining solid phase extraction (SPE) with gas purge-microsyringe extraction (GP-MSE) to purify sample extracts for the determination of polycyclic aromatic hydrocarbons (PAHs) in plant leaves. SPE exhibited good purification performance for the removal of polar lipids, while the GP-MSE technique effectively eliminated less-volatile lipids hence realizing zero damage to the instrument, and significantly improved the peak tailings. After ultrasonic extraction, the combined two-step clean-up procedure successfully removed over 99% of lipids from nineteen types of tree leaves, and PAHs in tree leaves were determined by GC-MS. The relative standard deviations (RSDs) for intra-day (n = 3) and inter-day (n = 3) analyses of PAHs in spiked willow samples were in the range of 0.8%-12.1% and 4.7%-15.3%, respectively. The recoveries of PAHs from spiked willow extracts ranged from 74 to 90%, with an average of 86%. The method detection limit (MDL) of PAHs in tree leaves ranged from 0.1 to 4.9 ng g-1 dry weight. In conclusion, the clean-up method in this study realized the analysis of PAHs in plant leaves with high accuracy, sensitivity and reproducibility. Most importantly, the two-step purification method significantly minimizes damage to the GC-MS system particularly to the column and ion source, which is beneficial to ensure continuous analysis of a large number of samples with good performance.

MeSH terms

  • Gas Chromatography-Mass Spectrometry / methods*
  • Limit of Detection
  • Lipids / isolation & purification
  • Pinus / chemistry
  • Pinus / metabolism
  • Plant Leaves / chemistry*
  • Plant Leaves / metabolism
  • Polycyclic Aromatic Hydrocarbons / analysis*
  • Polycyclic Aromatic Hydrocarbons / isolation & purification
  • Quercus / chemistry
  • Quercus / metabolism
  • Reproducibility of Results
  • Solid Phase Extraction / methods
  • Sonication

Substances

  • Lipids
  • Polycyclic Aromatic Hydrocarbons