Hach DR/850, Procedures Manual, Page: 427 / 460

427
Interferences
Summary of Method
This test measures all hydroxylated aromatic compounds,
including tannin, lignin, phenol and cresol. This method produces
a blue color proportional to the amount of these compounds
present in the sample. Report results as total tannin and lignin
expressed as mg/L tannic acid.
REQUIRED REAGENTS
Cat. No.
Tannin and Lignin Reagent Set (up to 100 tests) ..........................................................22446-00
Includes: (2) 675-49, (1) 2560-42
Quantity Required
Description Per Test Unit Cat. No
Sodium Carbonate Solution ..................................... 10 mL ................. 500 mL ..............675-49
TanniVer 3 Tannin-Lignin Reagent .......................... 1 mL .................. 100 mL ........... 2560-42
Water, deionized ....................................................... 25 mL ........................ 4 L ..............272-56
REQUIRED APPARATUS
Pipet Filler, safety bulb .................................................1 ...........................each ..........14651-00
Pipet, volumetric, Class A, 5.0 mL ...............................1 ...........................each ..........14515-37
Pipet, volumetric, Class A, 0.5 mL ...............................1 ...........................each ..........14515-34
Sample Cell, 10-20-25-mL, w/ cap ...............................2 .........................6/pkg ..........24019-06
OPTIONAL REAGENTS
Formaldehyde........................................................................................ 100 mL ............2059-32
Sodium Pyrophosphate, ACS...................................................................... 50 g ..........14295-25
Tannic Acid ............................................................................................... 113 g ..............791-14
Substance Interference Level and Treatment
Ferrous iron Causes a positive interference. Two mg/L of ferrous iron produces
a color equivalent to about 1 mg/L of tannic acid. To eliminate
interference of ferrous iron up to 20 mg/L, add one 0.2-g scoop of
sodium pyrophosphate to the sample before testing.
Sulfide Eliminated by adding 1 mL of formaldehyde to the sample before
testing the sample.
TANNIN AND LIGNIN,
continued