Colorimetry and High Performance Liquid Chromatography of Atrazine Residues in Soil: Comparison of Methods

Abstract

The colorimetric method for determining residual atrazine levels in soil is compared with reverse phase high performance liquid chromatography (HPLC). The soil samples are extracted with water-acetonitrile (10 + 90) and the filtrate is partitioned with methylene chloride. For the colorimetric analysis the organic phase is filtered through activity V alumina, collected, and evaporated to dryness. The residue is dissolved first in ethyl ether, and then in water as the ether is removed. The atrazine solution is buffered (citric acid, pH 7.0) and heated with added pyridine. When the reaction is complete, the product is complexed with ethylcyanoacetate, and the solution absorbance is measured at 550 nm. The complex obeys Beer’s law and has a sensitivity of 230 ng for a 1% full scale deflection at 1 AUFS. For the HPLC method, the methylene chloride extract is dried, the chromatographic solvent is quantitatively added (either chloroform or methanol), and the solution is analyzed with a UV detector at 254 nm. Minimum amount detectable for a 1% full scale deflection is 5 ng at 0.01 AUFS. Soil background interferences were investigated for both methods, and buffering the pyridine-triazine reaction solution was the most efficient method for removing the background for colorimetry. The recovery efficiencies for the colorimetric and HPLC methods were 45.5 ± 3.8% and 94.4 ± 3.4%, respectively.

Development of enzyme immunoassay for the detection of triazine herbicides

“…Because Federal and State regulations require pesticide residue analysis, there is a need to expand all available options for analysis. Currently, triazine residues are analyzed by either gas chromatography (Lee and Chau, 1983; Sirons et al, 1973) or high-performance liquid chromatography (Vermeulen et al, 1982;Vickrey et al, 1980). While these methods are accurate, they can f USDA-ARS.…”

HPLC determination of atrazine and principal degradates in agricultural soils and associated surface and ground water

“…HPLC is also applied to the determination of atrazine residues in soils. This method has been compared with a colorimetric method (Vickrey et al, 1980) and with a capillary column gas chromatographic method (Xu et al, 1986) for the parent herbicide and selected metabolites. Paired-ion HPLC has recently been reported for atrazine and hydroxyatrazine determination in soils (Wenheng et al, 1991).…”

Pesticides

“…Atrazine was determined in runoff water by reversed-phase HPLC after preconcentration on XAD-2 resin (311). HPLC was proven superior to colorimetry for the determination of atrazine residues in soil (511). Drying and storage of soil samples caused loss of extractable atrazine (481).…”