Determination of 3 Endocrine Disrupting Chemicals in Fishery Products by HPLC with Deep Eutectic Solvents Dispersive Liquid Liquid Microextraction-Solidification of Floating Droplets

Decanoic acid and geraniol were mixed in a 10 mL-glass tube at a molar ratio of 2:1, and then the mixture was heated in a water bath at 80℃ until a stable deep eutectic solvent (DES) was prepared. The solvent had the advantages of easy synthesis, low cost, low toxicity and high biodegradability. It was a new hydrophobic DES, which could be used for the microextraction of endocrine disrupting chemicals in fishery products. 1 g of crushed sample and 2 mL of acetonitrile were placed into a 5 mL-centrifuge tube and oscillated in a vortex at 2 000 r·min^-1 for 3 min. 400 μL of the supernatant was taken, and passed through 0.45 μm filter membrane. The obtained filtrate and 100 μL of DES were mixed and quickly injected into a 10 mL-centrifuge tube containing 5 mL of 80 g·L^-1 sodium chloride solution to complete the dispersion of DES. The above centrifuge tube was centrifuged at 3 500 r·min^-1 for 5 min, and then placed in an ice bath for solidification. The solidified sample was dissolved in 150 μL of methanol, and separated with Eclipse Plus C₁₈ as the separation column and a mixed solution of methanol and water in volume ratio of 90:10 as the mobile phase. Determination of 3 endocrine disrupting chemicals, including bisphenol A, 4-tertoctyl phenol and nonylphenol, was carried out at the excitation wavelength of 228 nm and the emission wavelength of 305 nm. As shown by the results, solidification of DES in ice bath could promote its separation from aqueous solution, which was simple and fast, and was conducive to the collection of extractant. Linear relationships between values of peak areas and mass fraction of 3 endocrine disrupting chemicals were found in the same range of 0.25-10 μg·g^-1, with the same detection limits (3S/N) of 0.075 μg·g^-1. This method was applied for determination of the blank spiked sample, with RSDs (n=5) of the determined values of intra-day and inter-day less than 4.0%. Test of recovery was made with the blank sample as the matrix by standard addition method, giving results in the range of 78.7%-91.6%.