Novel strategy for disposable pipette extraction (DPX): Low-cost Parallel-DPX for determination of phthalate migration from common plastic materials to saliva simulant with GC-MS

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 %).

MIL-88B(Fe)/cellulose microspheres as sorbent for the fully automated dispersive pipette extraction towards trace sulfonamides in milk samples prior to UPLC-MS/MS analysis

MIL-88B(Fe)/cellulose microspheres (MIL-88B(Fe)/CMs) were characterized by the means of SEM, XRD, TGA and N₂ adsorption-desorption test. The composite was used as the sorbent for fully automated dispersive pipette extraction (DPX), after introducing CMs as the support, the loss of MIL-88B(Fe) in DPX was avoided. Coupled to UPLC-MS/MS, the proposed method was employed for the analysis of trace sulfonamides (SAs) in milk samples. The parameters affecting the extraction efficiency, including pH of sample solution, the rate of aspiration and dispense, amount of the adsorbent, type and volume of elution solvent were optimized. Under the optimal conditions, good linearity (r ≥ 0.9978 for five analytes), high sensitivity (limit of detection: 0.00660-0.0136 μg kg^-1) and satisfactory recovery (69.8%-100.9%) were achieved. Furthermore, the sorbent showed desirable reusability over eight extraction cycles. Compared with other methods for the pretreatment of SAs, the proposed method showed advantages of high sensitivity, less sorbent consumption, environmental friendliness and automation, providing a promising protocol for sample preparation.