Rj. Vreeken et al., COUPLING OF ION-PAIR LIQUID-CHROMATOGRAPHY AND THERMOSPRAY MASS-SPECTROMETRY VIA PHASE-SYSTEM SWITCHING WITH A POLYMERIC TRAPPING COLUMN, Journal of chromatography, 654(1), 1993, pp. 65-77
A trapping column packed with polymeric material (PLRP-S) was used to
couple ion-pair liquid chromatography on-line with thermospray mass sp
ectrometry by phase-system switching. Phase-system switching was used
to remove non-volatiles from the eluent before it entered the mass spe
ctrometer. The total analytical system was optimized for chlorinated p
henoxy acids, which were separated as ion pairs with cetyltrimethylamm
onium bromide as ion-pair reagent. Parameters such as percentage of mo
difier and concentrations of ion-pairing reagent and buffer affected t
he sorption of the ion-pair on the trapping column. Desorption was eff
ected by protonation of the acids with, e.g., trifluoroacetic acid or
an ion-pair switch with, e.g., ammonium formate. The influence of pH a
nd modifier concentration during desorption was examined. In addition
to target-compound analysis, group-selective analysis was also demonst
rated. As an example, the system was used to identify chlorinated phen
oxy acids in river Rhine water.