Salting-out assisted liquid-liquid extraction coupled with HPLC-MS/MS for determination of 13 kinds of bisphenols and alkyl phenol compounds in liquid dairy products

Abstract

Objective: An analytical method was established for determination of 13 kinds of bisphenols and alkylphenol compounds in liquid dairy products by salting-out-assisted liquid-liquid extraction coupled with HPLC-MS/MS. Methods: The salting-out-assisted liquid-liquid extraction pre-treatment method was adopted, and the detection was performed in the mode of negative ion source multiple reaction monitoring （MRM） by triple quadrupole mass spectrometry, and quantitative analysis was performed by matrix external standard method. Besides, the effect of extraction solvent type, selection and the usage of salting-out agents on the recoveries were studied and the performance of the method was evaluated. Results: The liquid dairy products were liquid-liquid extracted with acetonitrile as extraction solvent and 0.4 g sodium chloride as salting-out agents. The 13 kinds of phenols had a good linear relationship, and the correlation coefficients were all ＞ 0.99. The standard recovery rates of milk and yoghurt were 81.5% to 118.1% and 80.8% to 107.6%, respectively, and the relative standard deviations were 1.89% to 12.3% and 1.12% to 11.9%. The detection limits were 0.15 to 0.75 μg/kg, and the quantification limits were 0.5 to 2.5 μg/kg. One of the commercially available liquid dairy product was found to contain 4-NP, and the concentrations was 9.28 μg/kg. Conclusion: The established method is suitable for the rapid detection of 13 kinds of bisphenols and alkylphenol compounds in liquid dairy products.

Keywords

• salting-out
• liquid-liquid extraction
• hplc-ms/ms
• liquid dairy products
• bisphenol
• alkylphenols
• detection