Determination of various fungicides in water by LC-DAD analysis

Benomyl as carbendazim (MBC), chlorothalonil, folpet, quinomethionate, and tetradifon are the most widely used fungicides in Trakya area (Turkey). This study presents a simple and rapid method for their analysis in surface water. They are separated on a 250x4.6 mm Luna C-18 column (0.8 ml min(-1) acetonitrile-water with 0.6% ammonia by gradient program) and detected using an UV-diode array detector. The water samples were pre-concentrated by solid-phase extraction with a C18 cartridge. Recovery rates of these compounds were found between 64 and 97% in water samples fortified at three different concentration levels. The inter- and intra-day relative standard deviations were in the range of 0.001-9.11%. The method's and instrumental detection limits ranged between 5-25 ng L-1 and 5-38 pg/injection, respectively. Results showed that the method developed can be used to detect pesticides in concentrations below the maximum residue limits (MRL) established by the European Union legislation

Genotoxic activities of drug-nitrite interaction products

At first 28 orally administered drugs, considered to be potentially nitrosatable on the basis of their chemical structure, have been nitrosated with nitrite under simulated stomach conditions. A maximum daily dose of each drug was incubated with a nitrite concentration that can be found after a normal meal in the stomach at 37degreesC over 1 h. Reaction was started at pH 6.8-7.0 and stopped at pH 2.0, so we had the same pH change that occurs in the stomach. Secondly the genotoxic activities of drug-nitrite interaction products were tested by the umu-test with Salmonella typhimurium TA 1535/pSK1002 as tester strain in the presence and absence of metabolic activation. By the umu-test, among the nitrosation products of drugs examined 22 products showed genotoxicity at different levels. Other six products showed negative results by the umu-test

Determination of triazines and N-methylcarbamate pesticides in water by high-performance liquid chromatography-diode array detection

A rapid and selective method for the simultaneous determination of triazine herbicides (atrazine, its degradation product desethylatrazine, simazine, prometryn, terbutryn) and N -methylcarbamate insecticides (propoxur, carbaryl and methiocarb) in surface water has been developed. A 0.5 L of the water sample was preconcentrated by passage through a 1 g C-18 solid-phase extraction cartridge. The retained compounds were eluted with 5 mL of methanol from the cartridge. The pesticides were separated and quantified by reversed-phase high-performance liquid chromatography with UV diode-array detection. Analytical separation was performed using a concave gradient elution with acetonitrile and water on a C-18 column. Prometryn and terbutryn were determined at 240 nm; propoxur, methiocarb at 204 nm and the others at 220 nm. Recoveries varied from 85 to 102% over concentrations at 0.025 and 0.2 mug L-1. The limits of detection for the compounds investigated are in the range of 0.005-0.012 mug L-1