A Comparison between a Two-Dimensional Liquid Chromatography System and a Traditional QuEChERS-LC Method with Regard to Matrix Removal and Matrix Effects in Pesticide Analysis Using Time-of-Flight Mass Spectrometry

In this study, a
fully automated two-dimensional liquid chromatography
(2D-LC) system was used for the investigation of the clean-up effect
and was compared with a traditional Quick Easy Cheap Effective Rugged
and Safe (QuEChERS) liquid chromatography (LC) method. The focus of
those investigations was on negative electrospray ionization (ESI)
mode. For that purpose, matrix fingerprinting profiles were created.
The results allowed a comparison of both methods regarding the estimation
of the number and the polarity of detected compounds. Moreover, the
results of the present study were compared with the results generated
in positive ESI mode (presented in a previous study). Furthermore,
the two methods were compared with regard to matrix effects (ME) of
321 analytes in positive ESI mode and 96 analytes in negative ESI
mode. In general, fewer compounds could be detected when 2D-LC and/or
the negative ESI mode was used. Especially, very polar compounds with m/z values >1000 could be separated
and
could not be detected anymore when 2D-LC was applied. Furthermore,
the best results were obtained for most analytes when 2D-LC was used,
although the extent of ME seemed to be higher with 2D-LC.