抄録
A highly sensitive method for the quantification of poly(oxyethylene)octylphenyl ether homologues (OPEs, where OPEn is an OPE homologue with n ethoxy units), which are nonionic surfactants, in environmental water has been developed using solid phase extraction (SPE) and liquid chromatography tandem-mass spectrometry (LC/MS/MS).
Methanol was added to environmental water samples as a preservative in 10% v/v concentration. The water samples were passed through a preconditioned SPE cartridge (EDS-1) to collect the OPEs, which were then eluted from the cartridge using a mixed solvent of methanol and ethyl acetate (1:1, v/v). The eluate was concentrated and dissolved in a mixed solvent of methanol and deionized water (Milli-Q) (1:1, v/v). The OPEs in the prepared solutions were then analyzed by LS/MS/MS.
The method detection limits (MDLs) for the detection of OPEs range from 0.17 ng/L for OPE5, to 2.0 ng/L for OPE1. The MDL of total OPEs is 6.1 ng/L, which was obtained by adding all the individual MDL values. The method quantification limits (MQLs) for quantification of OPEs range from 0.42 ng/L for OPE5, to 5.2 ng/L for OPE1. The MQL of total OPEs is 17 ng/L. The average recovery of OPEs in water samples ranged from 78% to 100% (c.v. 1.2-10%). The MQL of total OPEs was below the predicted "no effect" concentration used by the Ministry of the Environment, Government of Japan, for the initial assessment of ecological risk. In samples from Hokkaido, the OPEs in seawater were below the MQL and those in river water below the MDL when using this method.
