Benzyl 4 hydroxybenzoate

Bifonazole, butoconazole, clotrimazole, econazole, itraconazole, ketoconazole, miconazole, posaconazole, ravuconazole, terconazole, tioconazole, voriconazole and benzyl-4-hydroxybenzoate (Internal Standard, IS) (>98% purity grade), sodium phosphate monobasic and sodium phosphate dibasic (>99% purity grade), phosphoric acid (90% purity grade) and trichloroacetic acid (>99% purity grade) were purchased from Sigma-Aldrich (Milan, Italy).
The commercial drugs were obtained from a local Pharmacy after medical prescription. Both HPLC-grade Acetonitrile (AcN) and methanol (MeOH) were supplied by Carlo Erba (Milan, Italy) and were used without further purification. The water for HPLC analysis was generated by using a Millipore Milli-Q Plus water treatment system (Millipore Bedford Corp., Bedford, MA). Oasis HLB (1 mL, 30 mg) and Sep-Pak (1 mL, 50 mg) were obtained from Waters (Milford, MA), while Strata-X (1 mL, 30 mg) was purchased from Phenomenex (Torrance, CA). MEPS device (syringe) and replacement needle with C₁₈ stationary phase were purchased from SGE Analytical Science (Melbourne, Australia).

4-(Decyloxy)benzoic acid, benzyl-4-hydroxy benzoate, N,N′-diisopropylcarbodiimide (DIC), 4-(dimethylamino)pyridine (DMAP), 10% Pd-C, trimethoxysilane, karstedt’s catalyst (platinum (0)-1,3 divinyl-1,1,3,3-tetramethyldisiloxane complex solution in xylene) were purchased from Sigma Aldrich and used without further purification. The solvents used in the synthesis namely, dichloromethane, 1,4-cyclohexadiene, allyl alcohol, toluene, were of analytical grade. As received solvents were dried over molecular sieves (4 Å, 1–2 mm from Alfa Aesar) and the resulting anhydrous solvents were used to carry out the reactions. All the intermediate compounds were purified by column chromatography on silica gel (60–120 mesh) followed by repeated crystallization.

Methyl 4-hydroxybenzoate 99% (MeP), propyl 4-hydroxybenzoate 99% (PP), and benzyl 4-hydroxybenzoate 99% (BeP) were purchased from Sigma-Aldrich, ethyl 4-hydroxybenzoate 99% (EP) from Aldrich, and butyl 4-hydroxybenzoate 99% (BuP) from Fluka. These compounds were used as model aqueous pollutants. All reagents used in this work were of analytical grade and were used without any further purification. All solutions were prepared using water from a Millipore system (Direct-Q® Water Purification System- Merck Millipore).
Titanium(IV) isopropoxide (TIP) (97%) was purchased from Aldrich and used as a titanium source for the preparation of TiO₂ nanoparticles. A commercial form of TiO₂ (P25, crystalline composition: 80% anatase, 20% rutile, surface area 50 g/m²) was obtained from Evonik, Germany. PdCl₂ (5 wt% solution in 10 wt% HCl), NH₂NH₂·H₂O (reagent grade 50–60%), H₂PtCl₆ (99%), and AgNO₃ (99%) from Sigma-Aldrich were used as metal source in the preparation procedure. Ethanol (99.8%) was purchased from POLCHEM (Poland).
A photosensitizer (aluminum phthalocyanine chloride tetrasulfonic acid, AlPcS₄) from Frontier Scientific was immobilized in chitosan beads. Chitosan from crab (degree deacetylation ≥ 75%) used for carrier preparation was purchased from Sigma. Na₂HPO₄, NaOH, and all of p.a. quality (POCh, Poland) were used to prepare buffer solutions at pH 9.