Table IV. Conditions for the solid phase extraction of
phenoxyacid herbicides.
Tube dried for less than 1minute
Dry
Sample passed through tubeat rapid vacuum flow
rate
Sample flow rate
1.
3 x 2mLacidifiedmethanol
2.
Additional 2mLmethyl t-butyl ether (optional)
3.
Sample concentrated to 5mL (ambient
temperature, nitrogen purge)
Extraction
Inner surface of tube rinsedwith small amount of
acidifiedwater, if necessary
Wash
500mL or 1Lwater, pH adjusted to 2
Sample
1.
4mL acidifiedmethanol (0.01%phosphoric acid)
2.
4mL deionizedwater (pH=2)
Tube conditioning
6mL, 500mgResprepAH tube, 6mL/500mg
cat#26029
SPE tube
