Magnetic nanoparticle assisted supramolecular solvent extraction of triazine herbicides prior to their determination by HPLC with UV detection

We describe a method for the microextraction of the four model triazine herbicides cyanazine, simazine, prometon and propazine from water samples. It is based on the use of the supramolecular solvent decanoic acid and magnetic nanoparticles (NPs) which are applied to magnetically separate the decanoic acid micelles containing the extracted herbicides. Following desorption of the coating from the magnetic NPs with methanol, the solution was submitted to HPLC with UV detection. The pH values, amount of decanoic acid and sorbent, sample temperature, stirring rate, salt addition, and extraction time were optimized. Under optimal conditions, the preconcentration factors and relative recoveries for the four herbicides range from 183 to 256 and from 90.3 to 105.0 %, respectively. The analytical ranges extend from 0.3 to 250 mu ga (TM) mLaEuro3/4(1), and the limits of detection (LODs) are between 0.3 and 0.5 mu ga (TM) mLaEuro3/4(1) (based on an S/N ratio of 3). The precision of the method, expressed as relative standard deviation for extraction and determination of the 100 mu ga (TM) mLaEuro3/4(1) analytes in the samples solution is in the range from 4.6 to 6.5 %. We also critically compare the present method with various others.