193
SlJCiCiESTED READING
Isomer of LAS
SDS
Figure 7 .18. Structures of anionic surfactants.
SPE Conditions Used Sample Solutes Sorbent
Eluent Reference
Waste water (100 mL), no sample additions. Linear alkylsulfonate surfactants. 360 mg of C-8, but C-18 would work equally well. Precondition with 2 mL each of elution solvent acetonitrile or methanol, and distilled water. Elute with acetonitrile, but methanol works equally well, 2 mL. Anal. Chern., 62:2581-2586 (1990).
SPE Conditions Used Sample Solutes Extractant
Sorbent Eluent Reference
Soil or sediment (20 g), no sample additions. Anionic surfactants. 90% methanol/10% distilled water, extract twice with 20 mL each time with Soxhlet, heated vial, or accelerated solvent extractor. Dilute to 360 mL total with distilled water and then process by SPE. 360 mg of C-18, precondition with 2 mL each of methanol, ethyl acetate, methanol, and distilled water. Elute with methanol, 2 mL. Modified from Anal. Chern., 62: 2581 (1990).
SUGGESTED READING Brouwer, E. R., Liska, I., Geerdink, R. B., Frintrop, P. C. M., Mulder, W. H., Lingeman, H., and Brinkman, U. A. Th. 1991. Determination of polar pollutants in water using an on-line liquid chromatographic preconcentration system, Chromatographia, 32: 445-452. Font, G., Manes, J., Molto, J. C., and Pico, Y. 1993. Solid-phase extractions in multiresidue pesticide analysis of water, J. Chromatog., 642: 135-! 61.