Determination of triazine-herbicides in drinking water by a HPLC column switching technique

Quantification of triazine herbicides in soil by microwave-assisted extraction and high-performance liquid chromatography

A method for the determination of herbicides residues, triazine (atrazine, metribuzin, ametryn, and terbutryn), in soil samples with high-performance liquid chromatography (HPLC)-UV detection is described. The proposed method is based on microwave-assisted extraction (MAE) of soil samples for 4 min at 80% of 850-W magnetron outputs in the presence of mixture of solvents (methanol/acetonitrile/ethylacetate). Related important factors influencing the MAE efficiency, such as the solvent type and volume, irradiation energy, and time, were optimized in detail. Calibration curve ranges established using HPLC for metribuzin, atrazine, ametryn, and terbutryn are 1.0-19.0, 0.9-18.0, 0.6-11.0, and 0.7-11.0 µg mL( -1), respectively. The limits of detection of metribuzin, atrazine, ametryn, and terbutryn are 0.30, 0.24, 0.16, and 0.20 µg mL( -1) while limits of quantification are 1.0, 0.80, 0.50, and 0.60 µg mL( -1), respectively. A Plackett-Burman factorial design was used as a screening method in order to select the variables that influence MAE extraction. The recoveries of the method at three different spiked levels were assessed by analyzing real soil samples and were found to be in the range of 83.33 ± 0.12-96.33 ± 0.23 with good precision (<8%).

Combination of solid-phase extraction and field-amplified concentration for trace analysis of organonitrogen pesticides by micellar electrokinetic chromatography

An analytical method based on the combination of solid-phase extraction (SPE) and field-amplified concentration (FAC), with micellar electrokinetic chromatography (MEKC) was developed to extract, concentrate, separate, and quantitate six organonitrogen pesticides (metribuzin, bromacil, terbacil, hexazinone, triadimefon, and DEET) in drainage water. The recovery of the first five pesticides was over 85%, and the limit of detection was 0.8 ppb. Four advantages (enhanced enrichment and recoveries, reduced extraction time and interferences) of combining SPE with FAC for trace analysis of pesticides at the ppb level were demonstrated.

Occurrence and determination of pesticides in natural and treated waters

Pesticides as environmental pollutants are described in detail along with their sources and paths of entry into various elements of the environment. Comprehensive literature data on the concentration of these pollutants in natural and treated waters and wastewaters are discussed. A wide selection of isolation and preconcentration techniques for these pollutants in water is presented and discussed. An emphasis is put on solid-phase extraction. In the case of the authors' work, a more detailed description is given.