Mass spectrometric confirmation criterion for product-ion spectra generated in flow-injection analysis. Environmental application.

The suitability of a confirmation criterion recently recommended in the Netherlands for gas chromatography with mass spectrometric detection (GC-MS), was evaluated for flow-injection analysis (FIA) with atmospheric pressure chemical ionisation MS-MS detection. The main feature of the criterion is that the relative ion abundances of the four diagnostic ions are taken into account. That is, for lower-intensity peaks, relative standard deviations may be higher; this is an advantage with chemical ionisation MS procedures. A series of triazines and their degradation products were used as test compounds. Tap and surface water samples spiked at 0.33 microg/l were analysed by means of a selected reaction monitoring MS-MS procedure. For all analytes but hydroxysimazine (3 transitions), 4-9 transitions could be selected which invariably met the demands of the criterion. Some of the transitions used originate from the 37Cl isotopic mass of the parent compounds which provides additional structural information. Data for twenty surface water samples analysed by means of FIA-MS-MS as well as GC-MS and liquid chromatography with diode array UV and MS-MS detection gave essentially the same results over the 0.1-1.0 microg/l range. In two samples desethylatrazine was reported by FIA-MS-MS whereas this compound was not detected by GC-MS. For a first test, this is a promising result.