AOAC SPIFAN Nutrients ERP (December 7, 2022)

Amino-07 (Method) 10-2022 FOR ERP USE ONLY DO NOT DISTRIBUTE

(l)

Microcentrifuge vials.— 2 mL.

(m) Cryogenic vials.— 2 mL. (n) HPLC vials, septa, and caps.

C.

Reagents (a) Taurine.— Purity ≥ 99.5%; Sigma [or equivalent standard material]. (b) 13 C 2 15 N Taurine.— Purity ≥ 98%; Cambridge Isotope Laboratories [or equivalent standard material]. (c) Potassium hexacyanoferrate trihydrate.— Reagent grade. (d) Zinc acetate dihydrate.— Reagent grade. (e) Acetonitrile.— LC-MS grade (f) Formic acid.— LC ‒ MS grade. (g) Water.— Reagent grade (≥ 18 MΩ) . Reagent Preparation (a) Carrez I solution.— dissolve 15 g potassium hexacyanoferrate trihydrate in 100 mL water (expiry: 3 months). (b) Carrez II solution.— dissolve 30 g zinc acetate dihydrate in 100 mL water (expiry: 3 months). (c) Mobile phase (acetonitrile:water:formic acid 900:100:1 v/v/v).— Mix 900 mL acetonitrile, 100 mL water, and 1.0 mL formic acid in a 1 L Schott bottle (expiry 1 week ). Standard Preparation (a) Stable isotope-labeled stock standard ( SILSS ) ~0.1 mg mL ‒1 .— Store in freezer for up to 6 months. (i) Dispense the contents of a 10 mg vial of 13 C 2 15 N taurine into a 100 mL volumetric flask. (ii) Dissolve in ~9 mL of water; vortex mix thoroughly until dissolved. (iii) Make to volume with water; shake to mix. (iv) Immediately dispense aliquots (~1.3 mL) into cryogenic vials and freeze at < −15 °C.

D.

E.