Ammonium formate nh4cooh

The reference materials of L-BMAA hydrochloride and DL-2,4-diaminobutyric acid dihydrochloride (DAB) were purchased from Sigma-Aldrich (Oakville, ON, Canada), and N-2 (aminoethyl) glycine (AEG, A608975) standard was purchased from Toronto Research Chemicals Inc. (Toronto, ON, Canada). Acetonitrile, formic acid, and methanol came from Merck KGaA (Darmstadt, Germany) and were chromatographic grades. Ammonium formate (NH₄COOH) and trichloroacetic acid (TCA) were obtained from Sigma-Aldrich. The AccQ-Fluor Reagent Kit was obtained from the Waters (Taunton, MA, USA). Ultrapure water (resistivity > 18.2 MΩ·cm) was supplied by the MilliQ Water purification System (Millipore Ltd., SAS. Mosheim, France).

Enniatin B1 (ENNB1), deoxynivalenol (DON), midazolam (MDZ) and 4-hydroxymidazolam (4-OH-MDZ), mevastatine and bromocriptine (BCT), NADP⁺, NADPH, D-glucose 6-phosphate sodium salt, D-glucose 6-phosphate dehydrogenase from baker’s yeast (Saccharomyces cerevisiae), HEPES buffer, and ammonium formate (NH₄COOH) were purchased from Sigma-Aldrich (Millipore Sigma; St. Louis, MO, USA). Troleandomycin (TAO) was supplied by Santa Cruz Biotechnology, Inc. (Dallas, Texas, TX, USA). Atorvastatin (ARVS) lactone and the metabolites 4-OH-ATVS lactone and 2-OH-ATVS lactone were from Toronto Research Chemicals (North York, ON, Canada), and cortexolone was from Steraloids (Newport, RI, USA). Progesterone (PGS) and the metabolite 6β-OH-PGS were from Clearsynth (Mississauga, Ontario, Canada). Fluka (Millipore Sigma; St. Louis, MO, USA) supplied magnesium chloride hexahydrate (MgCl₂ × 6 H₂O). With exception of DON that was dissolved in 90% acetonitrile (MeCN), all of the stock solutions were prepared in HPLC grade methanol (MeOH).
Fisher Scientific provided chromatographic solvents, including MeCN, MeOH, and water (Optima, LC/MS grade) (Waltham, MA, USA). Formic acid (HCOOH) was purchased from Merck (Darmstadt, Germany).

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.

Working standards of AMP and cAMP were obtained from Sigma-Aldrich (St. Louis, MO, USA). The phosphodiesterase enzyme 3A (PDE3A) was purchased from Calbiochem (San Diego, CA, USA). Ammonium formate (NH₄COOH) and magnesium chloride (MgCl₂) were obtained from Sigma-Aldrich; all other chemicals were of Liquid Chromatography-Mass Spectrometry LC-MS grade (Sigma-Aldrich, St. Louis, MO, USA).

Deuterium-labeled ceramide LIPIDOMIX^® Mass Spec Standard Solution, EquiSPLASH™ LIPIDOMIX^® Mass Spec Standard Solution, and N-palmitoyl-d31-D-erythro-sphingosine (d31-Cer16:0, MW 569.1) were purchased from Avanti Polar Lipids (Alabaster, AL, USA). Deuterated cholesterol-2,2,3,4,4,6-d6 (d6-CH MW 392), deuterated cholesterol sulfate sodium salt (d7-CHS, MW 495), and hexadecanoic-9,9,10,10,11,11,12,12,13,13,14,14,15,15,16,16,16-d17 acid (d17-PA, MW 273), glyceryl trihexadecanoate-d98 (d98TG 48:0, MW 906), and n-hexadecyl-1,1,2,2-d4 hexadecanoate-16,16,16-d3 (d7WE, MW 488) were purchased from CDN Isotopes Inc. (Pointe-Claire, Quebec, Canada). Details on the internal standards used are reported in Table S1. HPLCMS-grade ethyl acetate, acetone, and chloroform were purchased from Carlo Erba (Milan, Italy). HPLCMS-grade acetonitrile, isopropanol, and methanol were purchased from Biosolve (Chimie SARL, Dieuze, France; BV, Valkenswaard, Netherlands). Ultra-HPLCMS-grade water was purchased from LiChrosolv by Merck (Darmstadt, Germany). Butylated hydroxytoluene (BHT) and the mobile-phase modifiers ammonium formate (NH₄COOH) and ammonium fluoride (NH₄F) were purchased from Sigma Aldrich (Milan, Italy). The mass calibration solution was prepared from Agilent Technologies Tuning mix (HP0321 solution, Agilent Technologies, Santa Clara, CA, USA) upon dilution in acetonitrile.

The analytical standard of CYCP (purity 99.0%) was provided by Shenyang Research Institute of Chemical Industry (Shenyang, China). Anhydrous MgSO₄, NaCl, sodium citrate tribasic dehydrate (Na₃Citrate), and sodium citrate dibasic sesquihydrate (Na₂HCitr) were purchased from Agilent Technologies (Palo Alto, CA, USA). LCMS-grade MeCN and formic acid (HCOOH) were obtained from DiKMA Technologies (Beijing, China). Ammonium formate (NH₄COOH; purity ≥ 99.995%) was purchased from Sigma-Aldrich (St. Louis, MO, USA). DPX tips (1250 µL) containing different amounts of SDVB and/or GCB were bought from DPX Technologies (Columbia, SC, USA). A manual pipette (100–1000 µL) used for DPX cleanup was obtained from INTEGRA Biosciences (Zizers, Switzerland). The water used in this study was ultrapure (18 MΩ cm) and was prepared by a LAB-UV-40 water purification system manufactured by Lab-Partner Technology Development (Changchun, China).
A 0.01 g sample of CYCP standard was dissolved in 10 mL of MeCN to prepare the stock solution at 1000 µg mL⁻¹. The solution was stored in an amber vial in a refrigerator at 4 °C, and its stability in three months was guaranteed by UHPLC-MS/MS monitoring. Working solutions with lower concentrations were freshly prepared from the stock solution before their use.