Octadecyl-fibrous mesoporous silica nanospheres coated 96-blade thin-film microextraction for high-throughput analysis of phthalic acid esters in food and migration from food packages

A high-throughput sample pre-treatment method combined with high-performance liquid chromatography (HPLC) was developed to analyze phthalates (PAEs) in food and food contact package samples. Thin film microextraction (TFME) in 96-blade format was used to pre-treat 96 samples simultaneously. Octadecyl groups functionalized fibrous mesoporous silica nanospheres, namely C18-FMSNs, were synthesized and used as TFME coating material. The coating was fabricated by spraying a slurry of C18-FMSNs and polyacrylontrile (PAN) mixture with a commercial portable spraypen. The prepared C18-FMSNs/PAN coatings exhibited good reproducibility, repeatability and reusability. The optimized TFME conditions for PAEs consisted of extraction at pH 4.0 for 50 min, and desorption by methanol/acetonitrile (25/75, V/V) for 40 min. The pretreatment time for each sample was approximately 1.3 min. This TFME-HPLC method showed good linearity for eight PAEs within the concentration range of 0.5–1000 ng mL−1, with the coefficients higher than 0.9972. The limits of detection and quantification were 0.096–0.26 ng mL−1 and 0.32–0.86 ng mL−1, respectively. The intra-day and inter-day RSD % were below 6.6 % and 8.4 %, respectively, indicating good precision. The PAEs analysis in real samples showed that dibutyl phthalate (DBP) of 2.3 ± 0.3 ng mL−1 and di-(2-ethylhexyl) phthalate (DEHP) of 5.5 ± 0.8 ng mL−1 in boxed milk, dimethyl phthalate (DMP) of 12.6 ± 0.8 ng mL−1, DBP of 3.2 ± 0.4 ng mL−1and DEHP of 14.3 ± 0.7 ng mL−1 in the simulated water migration of plastic box, as well as DMP of 19.0 ± 0.6 ng mL−1, DBP of 25.6 ± 0.9 ng mL−1 and DEHP of 49.5 ± 2.8 ng mL−1 in the simulated ethanol migration of plastic box were determined, respectively. In addition, the detection of PAEs in all the real samples showed good recovery ranging from 85.6 to 110 % and lower RSDs % (<7.2 %).