Mwf. Nielen, TRACE ENRICHMENT OF ENVIRONMENTAL-SAMPLES IN CAPILLARY ZONE ELECTROPHORESIS, TrAC. Trends in analytical chemistry, 12(9), 1993, pp. 345-356
Environmental ultra-trace analysis of aqueous samples can be successfu
lly performed using capillary zone electrophoresis (CZE) provided that
a suitable focusing injection technique is used. Emphasis is put on t
he injection and preconcentration of very large sample volumes using t
he field-amplified injection method. Sample pretreatment can be minimi
zed by using C18 membrane disks for simultaneous filtering and solid p
hase extraction. Desorption from the disks directly into the CZE sampl
e vials can be carried out using acetonitrile-buffer mixtures, thus pr
oviding a sample matrix having a sufficiently low and constant conduct
ivity. The potential of this approach for environmental trace analysis
is clearly demonstrated by the determination of phenoxy acid herbicid
es, as model compounds, in drinking- and river-water samples at the su
b-ppb level.