Easypure system

In this work, anatase TiO₂ NPs, isolated from a E171 sample (Pretiox AV-01-FG, Přerov, Czech Republic) of food and pharmaceutical grade, were studied. All chemicals were at least an analytical grade, provided by Sigma Aldrich (St. Louis, MO, USA), unless otherwise noted. Deionized water was obtained using the EasyPure system (Thermo Scientific, Waltham, MA, USA).

Acetonitrile and acetone were HPLC grade and purchased from Fisher Scientific (Fair Lawn, NJ, USA). Water was purified by an Easy pure system (Thermo Scientific, Waltham, MA, USA). Standard PAEs containing butyl benzyl phthalate, bis(2-ethylhexyl) phthalate, dibutyl phthalate, diethyl phthalate, dimethyl phthalate, and di-n-octyl phthalate (EPA 606-M, mix, 200 μg/mL in methanol) were purchased from Sigma Aldrich (Laramie, WY, USA). Ceramic homogenizer, dispersive SPE adsorbent (4000 mg MgSO₄, 1000 mg NaCl, 500 mg Na₂H citrate·1.5 H₂O, and 1000 mg Na₃ citrate·2 H₂O), clean-up adsorbent (150 mg PSA, 150 mg C18, 900 mg MgSO₄), and sodium chloride were purchased from Agilent Technologies (Lake Forest, CA, USA). For heavy metals analysis, HNO₃ (69%, hiperpur) and H₂O₂ (30% w/v 100 vol.) were purchased from PanReac AppliChem (AppliChem GmbH, Darmstadt, Germany). CRM-141R—trace elements in calcareous loam soil, CRM-142R—light sandy soil (trace elements), and CRM-143R—sewage sludge amended soil (trace elements) were prepared by Joint Research Centre, Ispra, and purchased by Sigma-Aldrich Chemie GmbH (Buchs, Switzerland). Standard solutions of Cd, Cr, Co, Cu, Ni, Pb, and Zn (1000 mg/dm³) were purchased by J. T. Baker (SAD, Instra).