Determination of triazine herbicides in cereals using dynamic microwave-assisted extraction with solidification of floating organic drop followed by high-performance liquid chromatography

A simple and cost-effective method of dynamic microwave-assisted extraction (DMAE) combined with solidification of floating organic drop (SFO) was developed for determining the five triazine herbicides in cereals. The approach combines the advantages of DMAE and SFO technique, and up to 15 samples can be treated simultaneously in 16 min. Firstly, triazine herbicides were extracted with 1 mL of methanol containing 90 mu L of 1-dodecanol and following with 10 mL of water under the action of microwave energy. After that, 1.5 g sodium chloride was added into the obtained extract, and the mixture was centrifuged and cooled. The 1-dodecanol drop which contained the target analytes was solidified and transferred for analysis by HPLC-UV. Limits of detection of the five triazines obtained were in the range of 1.1-1.5 ng g(-1). Relative standard deviations of intra- and inter-day tests ranging from 5% to 7% were obtained. The method was successfully applied to the analysis of ten cereals and the recoveries of the triazines for the spiked samples were in the range of 80-102%. The proposed method is an alternative approach to the analysis of triazine herbicides in complex solid samples, being more rapid and simpler compared with the traditional extraction method. (C) 2012 Elsevier B.V. All rights reserved.