Polypropylene centrifuge tubes

Methanol, acetonitrile, formic acid, ammonium formate, and water (all LC/MS or Optima grade) were obtained from Fisher Chemicals (Fair Lawn, NJ, USA). Ammonium hydroxide (NH₃ content 28–30%; analytical grade) was from Sigma-Aldrich (St. Louis, MO). Solid phase extraction (SPE) cartridges were 60-mg Oasis HLB with 30-µm particle size (Waters, Milford, MA). Borosilicate glass tubes, autosample vials, and polypropylene centrifuge tubes were purchased from Fisher Scientific. Milli Q water (>18 MΩ) was produced from a water purification system (Barnstead Nanopure). Multi-anion standards were from Sigma-Aldrich (St. Louis, MO, USA) and multi-cation standards were from Alltech (USA). Anatoxin-a, microcystin-LA, -LR, and -RR standards, as well as saxitoxin and cylindrospermopsin ELISA kits were all from Abraxis (Warminster, PA, USA). The 25-mm glass microfiber GF/A syringe filters were obtained from Whatman (GE Healthcare UK Limited, UK) and B-D 10-mL disposable syringes were from Becton Dickinson & Co (Franklin Lakes, NJ, USA). The IC eluents were sodium hydroxide (50%, w/w) for anion analysis and methanesulfonic acid for cation analysis.

All chemicals, solvents, milk (homogenized/whole milk (10% DV (daily value) fat), 2% reduced-fat (6% DV fat) milk, low-fat (3% DV fat) milk, fat-free milk, soy milk, almond milk, coconut milk, and milkadamia milk), and turmeric powder were purchased from commercial sources and used without purification. CUR, DMC, and BMC standards were purchased from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Deionized water (18 Ω) was obtained using a Millipore Milli-Q purification system (New Bedford, MA, USA). LC−MS grade acetonitrile and water were purchased from Fischer Scientific (Pittsburg, PA, USA). HPLC grade pure ethanol 200-proof was purchased from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Table 2 contains the nutrient label data on the milk samples. Extractions were carried out in 15 mL disposable polypropylene centrifuge tubes (Fisher Scientific, Pittsburgh, PA, USA). Poly (vinylidene difluoride) (PVDF) syringe filters with a pore size of 0.45 μm were purchased from National Scientific (Duluth, GA, USA). A Rival 700-Watt Microwave oven was used for warming the water and milk samples.