Sodium citrate dibasic sesquihydrate

Five types of mushrooms, oyster (Pasar, Malaysia), enoki (Pasar, Malaysia), shiitake (Chef, China), white button (Pasar, Holland), and mini portobello (Pasar, Malaysia), and chicken breast (Pasar, Malaysia) were purchased from a local supermarket (NTUC Fairprice, Singapore). Food grade ethanol (Echo Chemical Co., LTD, China) was used for extraction. Methyl undecanoate (C-11) standard, boron trifluoride (BF3), sulfuric acid, hydrochloric acid (HCl), sodium methoxide, methyl tert-butyl ester, sodium citrate dibasic sesquihydrate, GC-grade methanol and hexane were purchased from Sigma-Aldrich (St. Louis, MO, USA) along with petroleum ether (PE) (VWR, Singapore). Digestion tablets (Kjeltabs S-3.5, Foss™) for protein determination was purchased from Nexus Analytics (Singapore).

N-(2-aminoethyl) glycine (AEG) was obtained from Toronto Research Chemicals Inc. (North York, ON, Canada). β-N-methylamino-L-alanine hydrochloride (L-BMAA) (purity ≥ 97.0%) and L-2-2-diaminobutyric acid dihydrochloride (DAB) (purity ≥ 95.0%) were purchased from Sigma Aldrich (Oakville, ON, Canada). β-amino-N-methyl-alanine (BAMA) was acquired from the National Research Council of Canada (Halifax, NS, Canada). The isotope-labelled internal standard L-BMAA hydrochloride-d3 (BMAA-d3) was purchased from Abraxis, Inc. (Warminster, PA, USA).
Acetonitrile (ACN), methanol (MeOH), and water of HPLC quality were purchased from Fisher Scientific (Whitby, ON, Canada). Ammonium acetate (purity ≥ 98%), sodium citrate dibasic sesquihydrate (citrate; purity 99.0%), sodium tetraborate decahydrate (borate; purity 99.5%), potassium hydroxide (KOH; purity 90%), and trichloroacetic acid (TCA; purity ≥ 99.0%) were purchased from Sigma Aldrich (Oakville, ON, Canada). The derivatizing agent 9-fluorenylmethyl chloroformate (FMOC-Cl; 98.0% purity) was obtained from Alfa AeSar (Fisher Scientific, Whitby, ON, Canada).

Atropine ((±)-hyoscyamine), (±)-scopolamine hydrochloride, anisodamine, and homatropine hydrobromide were bought from Sigma-Aldrich as standards for tropane alkaloids (Madrid, Spain). For internal standards (IS), atropine-d5 and scopolamine-13C, d3 Hydrobromide were purchased from Toronto Research Chemicals Inc. (Toronto, ON, Canada). Before use, all standard solutions were maintained at room temperature for 30 min before being stored in amber vials in the dark at −20 °C.
Methanol (MeOH), acetonitrile (ACN), both HPLC-gradient grade, and formic acid were purchased from Merck (Darmstadt, Germany). Milli-Q plus system from Millipore (Molsheim, France) was used to purify the water, and it had a resistivity of 18.2 M cm.
For QuEChERS, magnesium sulfate and trisodium citrate dihydrate were purchased from PanReac (Barcelona, Spain), sodium chloride from Fluka (Seelze, Germany), and sodium citrate dibasic sesquihydrate from Sigma-Aldrich (Madrid, Spain). Agilent Technologies (Santa Clara, CA, USA) supplied the primary secondary amine-bonded silica (PSA) that was used for clean-up, in combination with anhydrous magnesium sulfate acquired from PanReac (Barcelona, Spain).