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Ammonium perfluorooctanoate as a volatile surfactant for the analysis of N ‐methylcarbamates by MEKC‐ESI‐MS
Author(s) -
Van Biesen Geert,
Bottaro Christina S.
Publication year - 2006
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200600076
Subject(s) - chemistry , chromatography , pulmonary surfactant , ammonium formate , analyte , analytical chemistry (journal) , ammonium , volumetric flow rate , mass spectrometry , perfluorooctanoic acid , organic chemistry , quantum mechanics , biochemistry , physics
Abstract Ammonium perfluorooctanoate (APFOA) was investigated as an MS‐friendly surfactant for the analysis of a mixture of ten N ‐methylcarbamates with MEKC‐ESI‐MS. Because of the relatively low boiling point of perfluorooctanoic acid (∼190°C), APFOA can be introduced into a mass spectrometer without the adverse effects of less volatile surfactants such as SDS. With a BGE consisting of 50 mM APFOA/isopropanol (IPA) 98:2 and with 30 kV applied, a very fast separation (∼6 min) was possible with only one pair of analytes comigrating. Using an experimental design with four factors (voltage, nebulizer pressure, concentration of APFOA, and concentration of IPA) we were able to resolve all analytes in just over 11 min. Sheath liquid composition and flow rate, drying gas temperature and flow rate, and fragmentor voltage were then optimized for maximum signal intensity and S/N. It was found that the faster method gave better S/N because of narrower peak widths, and detection limits in SIM mode were between 0.01 (aldicarb) and 0.08 mg/L (methomyl). Calibration curves were prepared with standards of 0.50, 1.00, and 2.00 mg/L for the analysis of samples obtained after SPE of tap water spiked with the ten N ‐methylcarbamates at a level of 10 µg/L. All analytes showed very good recoveries (>86%), except for the most polar analyte aldicarb sulfone (recovery of 73%), testifying for the potential use of APFOA for this kind of analyses.