Mgso4

HPLC grade reagents used for chromatography were obtained from Thermo Fisher Scientific (Waltham, MA, United States). All standard compounds used in the study were from Sigma-Aldrich Co. Ltd. (St. Louis, MO, United States). The QuEChERS kit used for extraction with a 50 ml tube with 4 g MgSO₄; 1 g NaCl; 1 g Na₃Citrate; 0.5 g Na₂HCitrate, purchased from Agilent (Santa Clara, CA, United States). Other commercial chemicals were of analytical grade and were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China).

Sodium alginate, mowiol™ 6-98 (PVA 6-98; polyvinylalcohol, Mw ∼47,000, 98% hydrolyzed), mowiol™ 10-98 (PVA 10-98; polyvinylalcohol, Mw ∼61,000, 98% hydrolyzed), calcium chloride anhydrous (CaCl₂, ≥96.0%), gallic acid (≥95.0%), and boric acid (B(OH)₃, ≥99.5%) were obtained from Sigma-Aldrich (St. Louis, MO, USA).
Glutardialdehyde (GA, 50% solution in water), absolute ethanol, L(+)-tartaric acid (≥99.5%), sodium hydroxide (NaOH, ≥99%), chloride acid (HCl), De Man Rogosa Sharpe (MRS) medium, solvents for HPLC analysis of chromatographic grade (ultra-pure water, H₂O; acetonitrile, ACN; acetic acid, CH₃COOH), Folin-Ciocalteu’s phenol reagent (≥99.5%; 2 N), and PTFE membrane filters (0.45 µm) were purchased from Merck KGaA (Darmstadt, Germany). Deionized water from a Millipore Milli-Q-P Plus system was used for preparing the aqueous solutions and for HPLC analysis.
QuEChERS extraction kits (salts—1 g of sodium citrate, 0.5 g of disodium citrate sesquihydrate, 4 g of magnesium sulfate (MgSO₄), and 1 g of sodium chloride—and dispersive solid-phase extraction tubes, 900 mg of MgSO₄, and 150 mg of primary secondary amine (PSA) sorbent) were purchased from Agilent Technologies (Santa Clara, CA, USA).
Ochratoxin A (from Petromyces alberiensis, ≥98%), was obtained from Sigma-Aldrich (St. Louis, MO, USA), and the stock solution (1 mg mL⁻¹ in absolute ethanol) was stored at −20 °C.

Formic acid, n-hexane, acetonitrile (HPLC grade) and methanol (HPLC grade) were purchased from Sigma-Aldrich (Steinheim, Germany) as well as standards: acrylamide (>99%), chlorogenic acid, caffeic acid, p-coumaric acid, catechin, rutin, D-(−)-fructose (≥99% GC), D-(+)-glucose (≥99.5% GC), and D-(+)-sucrose (≥99.5% GC). The QueChERS salt packet (4 g MgSO₄ and 0.5 g NaCl) and QueChERS d-SPE salts (150 mg MgSO₄ and 50 mg PSA) were purchased from Agilent Technologies (Santa Clara, CA, USA). Water was of Milli-Q quality (Millipore Corp., Bedford, MA, USA).

Analytical PAH standards (part number 31458) and deuterated Semi-Volatile Internal Standard Mix (part number 31006) were from Restek (Bellefonte, PA, USA), while optima LC-MS grade acetonitrile (ACN), methanol, dichloromethane, and sodium hydrogen carbonate were all purchased from Sigma Aldrich (St. Louis, Missouri, USA). Deionized (DI) water used for this work was purified to 18.2 MΩ-cm resistivity. NIST (Gaithersburg, MD, USA) standard reference material was organics in mussel tissue (SRM 1974b). QuEChERS AOAC extraction kits containing 6.0 g MgSO₄ and 1.5 g sodium acetate were provided as generous gifts from Agilent Technologies (Santa Clara, CA, USA). Stir bars were conditioned using a TC-2 tube conditioner (GERSTEL, Linthicum, MD, USA). Unless otherwise specified all other chemicals and reagents were of reagent grade or higher.

Dry ice (Airgas, Woodinville, WA, USA) was used in some homogenization procedures. LC/MS grade acetonitrile (Fisher Scientific, Hampton, NH, USA) and pouches containing 1.5 g of NaCl and 6 g of anhydrous MgSO₄ (United Chemical Technologies, Bristol, PA, USA) were used in the initial QuEChERS extraction. Polypropylene tubes (2 ml) containing 50 mg primary–secondary amine sorbent and 150 mg MgSO₄ (Agilent Technologies, Santa Clara, CA, USA) were used in the cleanup step. LC‐MS grade methanol and formic acid (Fisher) were used in LC mobile phase. Ethyl docosahexaenoate, N‐acetylhistamine, 5‐methylcytosine hydrochloride, tyramine, thymine, choline chloride, N‐acetyltyramine, N‐acetylcadaverine, 3‐methyladenine, N‐acetylhistamine, and creatinine (Fisher); N‐acetylputrescine hydrochloride (Sigma‐Aldrich, St. Louis, MO, USA); and 3‐methylguanine (Toronto Research Chem., North York, ON, Canada) were used as standards for identity confirmation.

Individual certified standards of ARs and PhACs (purity 95.19% to 99.9%) were acquired from Dr. Ehrenstorfer (Augsburg, Germany), Sigma-Aldrich (Augsburg, Germany) and European Pharmacopoeia Reference Standards (Strasbourg, France). Atrazine-d5, Carbendazim-d3, Coumachlor, Cyromazine-d4, Linuron-d3 and Pirimicarb-d6 (Dr. Ehrenstorfer and Sigma-Aldrich, 99.3–99.9% purity) were used as procedural internal standards (P-IS) and were maintained as described in the reference method [41 (link)]. These internal standards were added to the samples at the beginning of the procedure to account for various sources of errors throughout all stages in the method [58 ]. The list of the selected analytes, their classification, and their legal status are in Table 1.
LC-MS grade methanol (MeOH), acetonitrile (ACN) and formic acid (FA, HCOOH) were obtained from Honeywell (Morristown, NJ, USA). Ammonium acetate (NH₄CH₃CO₂) was purchased from Fisher Scientific (Loughborough, UK). AOAC method QuEChERS salts [59 (link)] (6 g of MgSO₄ and 1.5 g of CH₃COONa) were acquired in commercial premixes from Agilent Technologies (Palo Alto, CA, USA). The ultrapure water was produced in the laboratory using a Gradient A10 Milli-Q System (Millipore, Bedfore, MA, USA).