Sensitive determination of herbicides in food samples by nonaqueous CE using pressurized liquid extraction.

We have developed a method involving extraction with mixtures of solvents under pressure (pressurized liquid extraction (PLE)) for the determination of triazine herbicides in a series of samples from the food industry. The organic extracts obtained were subjected to a clean-up step with SPE, using Oasis MCX sorbents, after which they were analyzed by NACE. Potato was chosen as a representative matrix of horticultural products since it has a high water content. Spiked potato samples were used to optimize extraction conditions. In order to compare the results obtained with NACE, different studies were also conducted using HPLC. The detection limits in NACE were similar to those found with HPLC and were of the order of 10-15 microg/kg, depending on the analyte. Satisfactory results were obtained on applying the method proposed for the potato matrix (PLE with separation by electrophoresis) to other food matrices such as other tubercles, fruits, vegetables and cereals.