Microwave-Assisted Dispersive Liquid-Liquid Microextraction Combined with HPLC for the Determination of Three...

Microwave-assisted dispersive liquid-liquid microextraction (MADLLME) coupled with high-performance liquid chromatography (HPLC) with diode array detector was used for the extraction and determination of three biogenic amines (BAs), including tryptamine, histamine and phenylethylamine in beverages (beer, cherry juice and white spirit). Compared with solid-phase extraction, solid-phase microextraction and liquid-phase microextraction, which is more solvent use with lower extraction efficiency, this MADLLME method obviously shortened analytical time, the rapid heating of aqueous samples with non-ionizing electromagnetic radiation, a lower solvent use and enhanced extraction efficiency. Because of good extraction for three BAs, [3C6PC14][FeCl4] was used as an extraction solvent. We showed a tunable selectivity of magnetic ionic liquids (MILs) toward extracting BAs by changing anion or cation due to the modification of the interaction between the MIL and the BAs. Extraction conditions including the type and volume of extraction solvent, microwave power, microwave-assisted extraction time, sample pH, disperser and interference experiment were investigated. Under the optimal conditions, a good linear relationship was found in the concentration range of 100-2,000 ng mL-1 for three BAs with correlation coefficient (R2) of 0.995-0.999. The limit of detections (S/N = 3) and limit of quantitations (S/N = 10) were in the range of 3.46-4.96 ng mL-1 and 10.44-14.88 ng mL-1, respectively. The recoveries of three targets were in the range of 84.3-108.5%, and the relative standard deviations based on the peak areas for six replicate analyses of beverages spiked with 10, 50 and 100 ng mL-1 of each biogenic amine were lower than 7.9%. This method has also been successfully applied to analyze the real samples at three different spiked concentrations, and excellent results have been obtained.