Combination of Ultrasonic-assisted Aqueous Two-phase Extraction with Solidifying Organic Drop-dispersive Liquid–liquid Microextraction for Simultaneous Determination of Nine Mycotoxins in Medicinal and Edible Foods by HPLC with In-series DAD and FLD

Abstract

A novel method based on ultrasonic-assisted aqueous two-phase extraction (UAATPE) coupled with solidifying organic drop-dispersible liquid–liquid microextraction (SOD-DLLME) was developed for simultaneous determination of nine mycotoxins (aflatoxins of B1, B2, G1, G2, and M1, ochratoxin A, zearalenone, deoxynivalenol and patulin) in medicinal and edible foods by high-performance liquid chromatography (HPLC) with diode array detector (DAD) and fluorescence detector (FLD) in series. Using an aqueous two-phase system (ATPS) of acetonitrile and (NH4)2SO4 as the extractant, the effects of the ATPS composition, extraction temperature and time were investigated respectively to extract the mycotoxins from the samples. Also, SOD-DLLME conditions including type and volume of extractant and dispersant were optimized by the single factor experiments. The optimum conditions were as follows: the ATPS composition of 34.0% acetonitrile concentration (w/w) and 22.0% (NH4)2SO4 concentration (w/w), pH 6.0, extraction temperature 40 °C, ultrasonic time 10 min for UAATPE; 1-dodecanol 600 μL as extractant, acetonitrile 1.0 mL as dispersant, and vortex-assisted time 1.0 min for SOD-DLLME. By means of HPLC–DAD-FLD detection, nine mycotoxins had good linearity in the range of 0.5\u2009−\u2009200.0 ng/mL (R2\u2009≥\u20090.9991). LODs and LOQs were in the range of 0.01563\u2009−\u20090.5161 ng/mL and 0.05210\u2009−\u20091.720 ng/mL, respectively. The average recoveries and intra-day and inter-day precisions were 82.77\u2009−\u2009103.2%, 1.1\u2009−\u20093.4% and 1.5\u2009−\u20094.3%, respectively. The proposed method was successfully applied to simultaneous determination of multiple mycotoxins in black bean, black sesame, lotus seed, apricot kernel and litchi, demonstrating the presence of five different mycotoxins in these samples.