“…The tolerable concentration ratios with respect to 1.0 × 10 −6 mol/L -agonists for interference at the 5% level were over 1000 for Na + , K + , Cl − , NO 3− , Glucose, Starch, and EDTA; 100 for Alanine, Phenylalanine, Glycine, and Tryptophan; 50 for SO 4 2− , Mg 2+ and CO 3 2+ ; 10 for Cystine, Methionine, and Urea; 5 for Ca 2+ and Zn 2+ ; and 1 for Cu 2+ , Fe 3+ , Fe 2+ , and Mn 2+ . The main interferences are from heavy metal ions, which can be eliminated by using EDTA as a masking reagent.…”