Multi reax eu

According to Melo et al. (2021) [127 (link)], the lipid fraction extraction was accomplished by using absolute ethanol and n-hexane (HPLC grade) as solvents in constant agitation (Multi Reax EU, Heidolph, Schwabach, Germany). The final extract was used for vitamin E and fatty acid profile assessment.

The lipid fraction extraction was performed as described by Melo et al. (2021) [41 (link)] using absolute ethanol and n-hexane (HPLC grade) as solvents in constant agitation (Multi Reax EU, Heidolph, Germany). The final extract (1 mL) was divided for vitamin E (500 μL) and fatty acid profile (the other 500 μL) assessment.

Drug-free saliva blanks (400 μL) were enriched with 5 ng of IS + 6.25 ng of naproxen and 6-O-desmethylnaproxen and 400 μL of 0.5 M HCl for the first calibration standard point. For the standard calibration curve, eight serial dilutions were performed and the final mass was equal to 0.024 ng of naproxen and 6-O-desmethylnaproxen. The IS mass was the same for all curve points. These standard calibration curve points were extracted with 2 mL of ethyl acetate in 15 mL polypropylene tubes, shaken vigorously for 15 min at high speed (Heidolph Multi Reax EU, Heidolph Instruments GmbH & Co., KG, Schawaback, Germany) and centrifuged at 2,500 g at 4°C for 10 min. The organic phase (~1.8 mL) was then transferred and evaporated under airflow at room temperature in the chamber.
Saliva samples before naproxen alone and naproxen with esomeprazole intake (t = 0) were analyzed to ensure that there was no interference. After evaporation, the residues were dissolved in 100 μL methanol:10 mM ammonium acetate (70:30, v/v, isocratic), vortexed for 1 min, transferred to inserts, and then 5 μL of this solution was used for high-performance liquid chromatography.