Abstract:

Bisphenols （BPs）， which include bisphenol A and its analogs （such as bisphenol S， bisphenol AF， and bisphenol B）， are chemical substances that are synthesized artificially. BPs are used in epoxy resins and polycarbonate plastics and are widely found in food packaging and beverage containers. BPs are endocrine disruptors； hence， they can disrupt the natural hormonal activities of the human body， impact the neurological development of children， and affect intestinal microbial communities in the body， leading to obesity. Consequently， BPs pose threats to human health. The prepared dishes are usually using plastic packaging （containers， films， tubes， etc.）； consequently， BPs migrate from the packaging material to the food in the container is hot topic of wide concern. To address this issue， an efficient， simple and accurate method for the simultaneous determination of the 15 BPs content levels in prepared dishes using ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） was developed. The effects of the extraction solvent and its proportion， the amount of weighed matrix， and type of purifying agent on the responses and recoveries of the 15 BPs were investigated under the optimized MS conditions with the aim of determining the optimal sample-preparation conditions. The prepared dishes samples were crushed and evenly mixed， after which an internal standard solution containing a mixture of bisphenols was added and dispersed using 2.0 mL of ultrapure water. Acetonitrile （8.0 mL） was subsequently added， and the sample was extracted using vortex ultrasonication， centrifuged at 10 000 r/min for 10 min， and a 3.0-mL aliquot of the centrifuged supernatant was cleaned using a Captiva EMR-Lipid clean-up column， after which the purified liquid was subjected to UPLC-MS/MS. Analyses of response values， separation effects， and chromatographic peak shapes revealed that the Waters ACQUITY HSS T₃ column （100 mm×2.1 mm， 1.8 μm） optimally separated the 15 target BPs at a column temperature of 40 ℃， a flow rate of 0.2 mL/min， and an injection volume of 2.0 μL. A Waters ACQUITY BEH C₁₈ column （50 mm×2.1 mm， 1.7 μm） was used to trap and eliminate interference from exogenous BPs in the piping components. Gradient elution was performed using methanol and 0.01% （v/v） aqueous ammonia as mobile phases. Data were collected in electrospray negative-ion （ESI^-） and multiple reaction monitoring （MRM） modes， and quantified using the isotope internal standard method. The 15 BPs exhibited good linear relationships within their respective linear ranges under the optimized experimental conditions， with correlation coefficients （R²） greater than 0.999 0. The limits of detection （LODs） and limits of quantification （LOQs） were in the range of 0.01-0.45 μg/kg and 0.03-1.50 μg/kg， respectively. The recoveries and relative standard deviations （RSDs） of the 15 BPs in matrix sample of prepared dishes at low， medium， and high spiked levels were 70.9%‒105.8% and 0.6%‒9.1% （n=6）， respectively. The established method was used for the analytical determination of the 15 BPs in 30 prepared dishes samples， bisphenol A， bisphenol B， bisphenol C， bisphenol G， bisphenol S and bisphenol AF were detected in 11 samples， with bisphenol A exhibiting the highest detection rate of 16.7%， followed by bisphenol C， bisphenol G， bisphenol B， bisphenol AF， and bisphenol S， with values of 10.0%， 10.0%， 6.67%， 6.67% and 3.33%， respectively. The median contents of bisphenol G， bisphenol B， bisphenol A， bisphenol C， bisphenol S， and bisphenol AF were 4.15， 3.25， 2.68， 2.16， 1.49， and 0.47 μg/kg， respectively， with two BPs detected in 16.7% of the samples. The developed method involves simple pretreatment， is highly precise and sensitive， and is capable of accurately and qualitatively analyzing the 15 BPs in prepared dishes.

Key words: bisphenols （BPs）, ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）, prepared dishes, solid phase extraction