Published:Journal of Chromatographic Science,
ISSN 0021-9665Volume
39, Number 8, August 2001, pp. 325-331
Comparison
of Extraction Methods to Monitor Pesticide Residues in Surface WaterEtelka
Majzik-Solymos1, Éva Visi2,*, Gabriella Károly3, Borbála
Beke-Berczi4, and László Györfi5 1Plant Health and Soil Conservation Station (PHSCS) of Fejér County,
Velence, Hungary; 2PHSCS of Somogy County, Kaposvár, Hungary; 3PHSCS
of Veszprém County, Csopak, Hungary; 4PHSCS of Szolnok County, Szolnok;
and 5Plant Health and Soil Conservation Center, Budapest, Hungary
A
regular monitoring program to study the pesticide concentration in surface waters
has been carried out since 1976 in Hungary by the National Plant Protection
Organization of the Ministry of Agriculture and Regional Development jointly
with the Regional Water Authorities. At the beginning of this program a liquid–liquid
partition method is used to extract the pesticides from water samples. After
checking the pH value, one sample aliquot is extracted to analyze the basic
and neutral compounds. Another aliquot is acidified to pH 2 and extracted to
analyze acidic compounds. Disadvantages of this method are high solvent consumption
and the need to apply solvents (methylene chloride and diethyl ether) that are
harmful to human health. Therefore, the solid-phase extraction method has been
introduced. This method has another advantage in that by using the vacuum manifold
a number of samples can be extracted simultaneously depending on the capacity
(number of ports) of the manifold. Three types of cartridges (LiChrolut EN,
ISOLUTE ENV+, and Carbograph) are tested. The suitability and reproducibility
of the extraction on various cartridges is studied and compared through recovery
experiments. Recoveries are done for 22 active ingredients at spiking levels
of 1–5 times the limit of determination (in the range of 0.05–2.5
µg/L) with each extraction method. Individual recovery values as well
as average recoveries for all methods are between 70% and 100%, with the relative
standard deviation generally below 20%. Carbograph is the only cartridge among
those studied that can be used to extract both neutral and acidic compounds
in one sample loading step using two different consecutive elution steps.
Reproduction
of editorial content of this journal is prohibited without publisher’s
permission.
This
article is available in its entirety by fax for $4.00 per
page.
Visa or MasterCard accepted.
To
order electronicallyclick here or call: 847-647-2900 ext. 1323 or fax request to: 847-647-1155.
Please
indicate JCS volume and issue along with
page numbers.
