Detection of s-Triazine pesticides in natural waters by modified large-volume direct injection HPLC

There is a need for simple and inexpensive methods to quantify potentially harmful persistent pesticides often found in our water-ways and water distribution systems. This paper presents a simple, relatively inexpensive method for the detection of a group of commonly used pesticides (atrazine, simazine and hexazinone) in natural waters using large-volume direct injection high performance liquid chromatography (HPLC) utilizing a monolithic column and a single wavelength ultraviolet¿visible light (UV¿vis) detector. The best results for this system were obtained with a mobile phase made up of acetonitrile and water in a 30:70 ratio, a flow rate of 2.0 mL min-1, and a detector wavelength of 230 nm. Using this method, we achieved retention times of less than three minutes, and detection limits of 5.7 ?g L-1 for atrazine, 4.7 ?g L-1 for simazine and 4.0 ?g L-1 for hexazinone. The performance of this method was validated with an inter-laboratory trial against a National Association of Testing Authorities (NATA) accredited liquid chromatography¿mass spectrometry/mass spectrometry (LC¿MS/MS) method commonly used in commercial laboratories.