Formic acid hcooh

Used palm oil for preparing recycled palm oil (RPO) was purchased from a Nonthaburi local market, Nonthaburi province (acid value of 1.41 mg KOH/g and iodine value of 40.1 mg I₂/g). The used palm oil was first filtered before modification. Hydrogen peroxide (H₂O₂, 35%) and sodium hydrogen carbonate (NaHCO₃, >90%) were purchased from Ajax Finechem (Sydney, Australia). Formic acid (HCOOH, 98%) was purchased from Fisher Chemical (Shanghai, China). Ethyl acetate (CH₃COOC₂H₅, >99%) was purchased from RCI Lab-Scan Limited (Bangkok, Thailand). Polymeric diphenylmethane diisocyanate (P-MDI, 31.5% NCO content, functionality = 2.7) was purchased from BASF (Ludwigshafen, Germany). T-12 (dibutyltin dilaurate, 95%) was purchased from Fluka Chemie AG CH-9471 Company (Darmstadt, Germany). Dabco 33LV (33% triethylene diamine in propylene glycol) was purchased from Evonilk Goldschmidt GmbH (Essen, Germany). Silicone surfactant (TEGOSTAB^® B8110) was obtained from Gold-Schmidt (Berlin, Germany). Dried water hyacinth was purchased from Suphanburi province, Thailand. Commercial polyurethane foam, Polyurethane foam/glass fiber, and polyester foam were purchased from a convenience store, Nonthaburi province, Thailand.

Non-glutinous rice flour (Erawan brand) was purchased from Do Heng Rice Vermicelli Factory Co., Ltd. (Nakhon Prathom, Thailand). Baking powder double-acting formula, containing 30% of sodium bicarbonate (NaHCO₃), 24% of disodium pyrophosphate (Na₂H₂P₂O₇) and 16% of monocalcium phosphate (Ca(H₂PO₄)₂), was purchased from Best Food brand (Chachoengsao, Thailand). Polyvinyl alcohol (PVOH), a moisture resistance, with a molecular weight of 72,000 g/mol was purchased from Krungthepchemi Co., Ltd. (Bangkok, Thailand). Used palm oil for preparing recycled palm oil (RPO) was purchased from a Nonthaburi local market, Nonthaburi province (acid value of 1.41 mgKOH/g and iodine value of 40.1 mg I₂/g). The used palm oil was first filtered before modification. Hydrogen peroxide (H₂O₂, 35%) was purchased from Ajax Finechem (Sydney, Australia). Formic acid (HCOOH, 98%) was purchased from Fisher Chemical (Shanghai, China). Ethyl acetate (CH₃COOC₂H₅, >99%) was purchased from RCI Lab-Scan Limited (Bangkok, Thailand). Distilled water, purchased from Yod Nam Distilled Water (Nakhon Prathom, Thailand), was used to prepare gelatinized starch before foam preparation. All ingredients were dried before use.

The standards of pesticides were purchased from Dr. Ehrenstorfer GmbH (Augsburg, Germany). For acetamiprid, chlorantraniliprole, and iprovalicarb, the mix DRE-Q60 004725 of 10 µg/mL each was used, while for the other three pesticides, custom individual 10 µg/mL standard solutions in acetonitrile were used, also from Dr. Ehrenstorfer. Dilutions were conducted in acetonitrile to the desired concentrations, and then a final dilution was made by transferring 0.25 mL of the standard solution, adding 10 µL of the internal standard (TPP 5 µg/mL), and then 0.74 mL of ultrapure water. The Quick QuEChERS-Medium Cartridge was purchased from United Chemical Technologies (Bristol, PA, USA); the extraction salts including magnesium sulphate (MgSO₄), sodium chloride (NaCl), acetonitrile, 2-propanol, acetone were from Merck KGaA (Darmstadt, Germany); formic acid (HCOOH; purity ≥ 95%) was from Fisher Chemical; and ammonium formate (HCO₂NH₄) from Sigma Aldrich (St. Louis, MO, USA). Methanol was supplied by HiPerSolv, VWR Chemicals (Radnor, PA, USA). A Kinetex biphenyl chromatography column (2.6 μm, 4.6 × 150 mm) was purchased from Phenomenex (Torrance, CA, USA) and ultrapure water was obtained by a Milli-Q water purification system from Millipore (Bedford, MA, USA).

Fourteen reference standards of ginsenosides Rb1, Rb2, Rb3, Rc, Rd, Re, Rf, Rg1, Rg2, Rg3, Rh1, Rh2, F2, and 24(R)-pseudoginsenoside F11 (p-F11) were purchased from Star Ocean Ginseng Ltd. (Suzhou, China). The purities of the fourteen standards were no less than 98.0%. Their structures are shown in Figure 1. LC–MS-grade acetonitrile (MeCN) and water were supplied by Merck (Phillipsburg, NJ, USA). LC-grade methanol (MeOH) and formic acid (HCOOH) were purchased from Fisher Chemical (Pittsburgh, PA, USA). Water (for extraction) was obtained from a Milli-Q Ultra-pure water system (Millipore, Billerica, MA, USA). Other reagents used in this study were of analytical grade.

The 11 pharmaceuticals studied are classified following their Anatomical Therapeutic Chemical Classification code (ATC). They all were purchased from Sigma-Aldrich (St. Louis, MO, USA) with a purity range of 98–99%. Furthermore, atenolol-d7, lidocaine-diethyl-d10 and acetaminophen-methyl-d₃ were acquired also at Sigma-Aldrich and were used as internal standards. HPLC grade methanol and acetonitrile (ACN) were supplied by VWR Chemicals (Leuven, Belgium). Ammonium formate (NH₄COOH) and ammonium hydroxide (NH₄OH) were supplied by Sigma-Aldrich (St. Louis, MO, USA). Hydrochloric acid 37% (HCl) and formic acid (HCOOH) were purchased from Fisher Scientific (Bridgewater, MA, USA). Ultra-pure Milli-Q water was obtained through a Millipore purification system (Millipore, Bedford, MA, USA). Standard stock solutions were prepared in amber glass vials at a concentration of 1000 mg L⁻¹ in methanol, and working solutions were prepared between 1 and 2500 µg L⁻¹ in 90% of Milli-Q water and 10% of methanol.