Methodology for Removing Dihalomethane Carryover from Solid-Phase Microextraction Fibers
Solid-phase microextraction (SPME) in conjunction with gas chromatography–mass spectrometry (GC–MS) is a simple and effective way to sample analytes. Ordinarily the coated fiber is rid of compounds during desorption in the GC, allowing for the analysis of a new sample. Carryover of the analyte between samples, however, is a problem with many chemicals. Our data shows that heating the fiber in a high temperature injection port for only 2 min between runs prevents carryover. The short heating between samples improves the linearity of the peak area versus concentration relationship over four orders of magnitude of concentration, with a limit of detection below 10-7 M in every case. Although carryover is an acknowledged problem with SPME fibers, such short conditioning steps are rarely considered as a means to eliminate it; this study suggests that they should be evaluated as an option.