AOAC 2018 Methods

bromide in 10 mL of ultra-pure water. Transfer 180 µL of the concentrated solution into an empty conical flask. Add 0.3 mL of sulfuric acid and 5.5 mL of ultra-pure water. Shake vigorously. (b) Sodium hydrogen carbonate solution (0.6%, w/v) .- Weigh 0.6 g of sodium hydrogen carbonate in a 100 mL volumetric flask and fill up to the mark with ultra-pure water. Use ultrasonic bath to ensure the complete dissolution of the reagent. (c) Sulfuric acid/methanol solution (1.8% v/v ).- Pipette 1.8 mL of sulfuric acid in a 100 mL volumetric flask and fill up to the mark with methanol. (d) Sodium hydrogen carbonate solution (saturated) .- Weigh 9.6 g of sodium hydrogen carbonate in a 100 mL volumetric flask and fill up to the mark with ultra-pure water. Use ultrasonic bath to ensure the dissolution of the reagent. (e) Sodium sulfate solution (20%, w/v ).- Weigh 20 g of sodium sulfate in a 100 mL volumetric flask and fill up to the mark with ultra-pure water. Use ultrasonic bath to ensure the complete dissolution of the reagent. (f) Phenylboronic acid solution (4% w/v) .- Dissolve 0.4 g of phenylboronic acid (PBA) in 10 ml of diethyl ether. Use ultrasonic bath to ensure the complete dissolution and shake vigorously. (g) N-Hexane-Acetone solution (1:1 v/v) .- Prepare a solution of n-hexane-acetone in the ratio 1:1 (v/v). Mix thoroughly and store in screw capped vessel of 250 ml. (h) N-hexane:ethyl acetate (85:15 v/v) elution solvent.- Prepare a solution of n-hexane-ethyl acetate in the ratio 85:15 (v/v). Mix thoroughly and store in screw capped vessel of 250 ml. Prepare Stock Standard solutions. These individual stock solutions, as well as all other diluted solutions are stable for up to one year if stored in the refrigerator at 4°C. For each of the individual stock solution, record exact weigh of pure standard with a 0.1 mg precision and recalculate exact concentration of stock solution. (a) 1,2-Dipalmitoyl-3-chloropropanediol (PP-3MCPD) (1mg/mL, to be recalculated according to exact weigh) .-Weigh 10 mg of PP-3MCPD in a 10 mL volumetric flask and record exact weigh. Fill up to the mark with toluene and ensure that the standard is completely dissolved in the solvent. (b) 1,2-Dipalmitoyl-3-chloropropanediol-d5 (PP-3MCPD-d5) (1mg/mL, to be recalculated according to exact weigh) .-Weigh 10 mg of PP-3MCPD-d5 in a 10 mL volumetric flask. Fill up to the mark with toluene and ensure that the standard is completely dissolved in the solvent. (c) 1,3-Dipalmitoyl-2-chloropropanediol (PP-2MCPD) (1mg/mL, to be recalculated according to exact weigh) .-Weigh 10 mg of PP-2MCPD in a 10 mL volumetric flask. Fill up to the mark with toluene and ensure that the standard is completely dissolved in the solvent. (d) 1,3-Dipalmitoyl-2-chloropropanediol-d5 (PP-2MCPD-d5) (1mg/mL, to be recalculated according to exact weigh) .-Weigh 10 mg of PP-3MCPD-d5 in a 10 mL volumetric flask. Fill up to the mark with toluene and ensure that the standard is completely dissolved in the solvent. (e) Glycidyl Palmitate (Gly-P) (1mg/mL, to be recalculated according to exact weigh) .-Weigh 10 mg of Gly-P in a 10 mL volumetric flask. Fill up to the mark with toluene and ensure that the standard is completely dissolved in the solvent. (f) Glycidyl Palmitate-d5 (Gly-P-d5) (1mg/mL, to be recalculated according to exact weigh) .- Weigh 10 mg of Gly-P-d5 in a 10 mL volumetric flask. Fill up to the mark with toluene and ensure that the standard is completely dissolved in the solvent.

E. Stock Standard Preparation