Extraction of eight triazine and phenylurea herbicides in yogurt by ionic liquid foaming-based solvent floatation

The ionic liquid foaming-based solvent floatation (ILF-SF) was developed for extracting triazines and phenylureas from yogurt. These analytes were separated and determined by high performance liquid chromatography. Some experimental parameters, such as the pH value of floatation solution, extraction solvent, kind of ionic liquid and floatation time were investigated and optimized. The mixture of n-propyl alcohol and ethyl acetate was used as extraction solvent and 1-hexyl-3-methylimidazolium hexafluorophosphate was used as foaming agent. The precision and recoveries of eight herbicides vary from 0.17 to 6.90% and from 86.5 to 118.7%, respectively. The detection limits for simeton, simazine, chlortoluron, isoproturon, ametryn, propazine, prometryne and prebane are 0.59, 0.44, 0.44, 0.46, 0.32, 1.01. 0.34 and 0.23 mu g L-1, respectively. The enrichment factors for the solvent floatation range from 11.6 to 18.6 for the eight herbicides. (C) 2011 Elsevier B.V. All rights reserved.