Comparison of Off-Line and On-Line Solid Phase Extraction and High Performance Liquid Chromatographic Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in Water

Methods of the off-line and on-line solid phase extraction (SPE) combined with liquid chromatographic (LC) analysis were compared in respects of separation effect, breakthrough volume, precision and detection limits for polycyclic aromatic hydrocarbons (PAHs). Results showed that the on-line mode is slightly preferred than the off-line one except for the early eluting compounds, naphthalene and biphenyl, due to the overshadowing of the matrix. Measurement of PAHs was performed for surface water with both off-line and on-line systems. Comparison results have shown that four polycyclic aromatic hydrocarbons: naphthalene, fluorene, phenanthrene and anthracene were detected in the surface water and both the techniques fit linear regression mode for fluorene, phenanthrene and anthracene at trace levels. With removal of the matrix interference, such as humic acids and fulvic acids, the precision of on-line system for naphthalene could be improved.