Determination of six parabens residues in fresh-cut vegetables using QuEChERS with multi-walled carbon nanotubes and high performance liquid chromatography-tandem mass spectrometry

Authors: SONG, SHUANGYU - CHINA AGRICULTURAL UNIVERSITY; ZHANG, ZIHAO - CHINA AGRICULTURAL UNIVERSITY; PAN, CANPING - CHINA AGRICULTURAL UNIVERSITY; HAN, LIJUN - CHINA AGRICULTURAL UNIVERSITY; Sapozhnikova, Yelena

Submitted to: Journal of Food Analytical Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2017
Publication Date: 6/2/2017
Citation: Song, S., Zhang, Z., Pan, C., Han, L., Sapozhnikova, Y.V. 2017. Determination of six parabens residues in fresh-cut vegetables using QuEChERS with multi-walled carbon nanotubes and high performance liquid chromatography-tandem mass spectrometry. Journal of Food Analytical Methods. 10:3972-3979.

Interpretive Summary: Parabens are antimicrobial preservatives used to extend the shelf-life of food products, including meat, milk, seafood, and fresh-cut vegetables. Effects of parabens on human health are not thoroughly understood, but there is a concern due to their potential endocrine disruptive properties. Therefore, simple and efficient analytical methods are needed to test food products for parabens to shed light on their occurrence in foods. A new method was developed to test for six parabens most commonly used as preservatives in fresh cut vegetables: potato, broccoli, carrot, celery and cabbage. To achieve efficient cleanup of pigmented vegetables, a novel sorbent - multi-walled carbon nanotube (MWCNTS) material was tested, and provided efficient removal of chlorophyll. The developed method was successfully validated, and applied for residual analysis of the selected parabens in 55 vegetable samples collected from the market in China. Methyl paraben was found in only one sample (celery). The developed method can be successfully used for fast and efficient analysis of parabens in vegetables, and can be easily extended to other types of foods.

Technical Abstract: In this study, an optimized QuEChERS sample preparation method was developed to analyze residues of six parabens: methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, and isobutyl-paraben in five fresh-cut vegetables (potato, broccoli, carrot, celery and cabbage) with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Homogenized samples were extracted using acetonitrile, and the extracts were cleaned with the novel sorbent - multi-walled carbon nanotubes (MWCNTS). MWCNTs provided 84-94% removal efficiency of chlorophyll and lower matrix effects compared to commonly used primary secondary amine (PSA) sorbent. Selected parabens were separated by HPLC with isocratic elution using acetonitrile and 0.1% (V/V) formic acid solution and determined by triple quadrupole MS/MS. The method validation results showed that recoveries were at 70%-120% with RSDs <20%. Calibration curves showed linear responses of six parabens with R2>0.99. Fifty fresh-cut vegetable samples from different farmer markets in Beijing, China were collected to detect the parabens residues, and only one sample was tested positive with methyl paraben concentration at 80.8 ug/kg.