LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 127)

INTERFERENCES: The following ions interfere in concentrations greater than
those listed.
Ion mg/L Ion mg/L
Cd(II) 1 Cr(III) 10
Al (III) 5 Ni(II) 20
Mn (II) 5 Co (II) 30
Fe (III) 7 CrO4(II) 50
Fe (II) 9
ZINC - LOW RANGE 2/3 COD PLUS TEST PROCEDURES 6/02