| Abstract: | Solid-phase extraction (SPE) and enzyme-linked immunosorbent assay (ELISA) were coupled for automated trace analysis of pristine water samples containing 2-chloro-4-ethylamino-6-isopropylamine-s-triazine (atrazine) and 2-chloro-2???,6???-diethyl-N-(methoxymethyl)acetanilide (alachlor). The isolation of the two herbicides on a C18-resin involved the selection of an elution solvent that both removes interfering substances and is compatible with ELISA. Ethyl acetate was selected as the elution solvent followed by a solvent exchange with methanol/water (20/80, % v/v). The SPE-ELISA method has a detection limit of 5.0 ng/L (5 ppt), >90% recovery, and a relative standard deviation of ??10%. The performance of a microtiter plate-based ELISA and a magnetic particle-based ELISA coupled to SPE was also evaluated. Although the sensitivity of the two ELISA methods was comparable, the precision using magnetic particles was improved considerably (??10% versus ??20%) because of the faster reaction kinetics provided by the magnetic particles. Finally, SPE-ELISA and isotope dilution gas chromatography/ mass spectrometry correlated well (correlation coefficient of 0.96) for lake-water samples. The SPE-ELISA method is simple and may have broader applications for the inexpensive automated analysis of other contaminants in water at trace levels. |
| Genre: | Article |
| ProdID: | 70017464 |
| Citation Author: | Aga, D. S.; Thurman, E. M. |
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| Citation End Page: | 2898 |
| Citation Issue: | 20 |
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| Citation Language: | English |
| Citation Larger Work Title: | Analytical Chemistry |
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| Citation Number Of Pages: | 5 |
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| Citation Search Results Text: | Coupling solid-phase extraction and enzyme-linked immunosorbent assay for ultratrace determination of herbicides in pristine water; 1993; Article; Journal; Analytical Chemistry; Aga, D. S.; Thurman, E. M. |
| Citation Start Page: | 2894 |
| Citation Volume: | 65 |
| Citation Year: | 1993 |
| Type: | citation/reference |
| Text: | Coupling solid-phase extraction and enzyme-linked immunosorbent assay for ultratrace determination of herbicides in pristine water; 1993; Article; Journal; Analytical Chemistry; Aga, D. S.; Thurman, E. M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Fri, 1 Jan 1993 00:00 -0600 |
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