LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 110)

POTASSIUM
TETRAPHENYLBORON METHOD • CODE 3639-SC
QUANTITY CONTENTS CODE
30 mL *Sodium Hydroxide, 1.0N
*4004WT-G
5 g *Tetraphenylboron Powder
*6364-C
1 Spoon, 0.05 g, plastic
0696
*WARNING: Reagents marked with a * are considered hazardous substances. Material
Safety Data Sheets (MSDS) are supplied for these reagents. For your safety read label
and accompanying MSDS before using.
Potassium, as the seventh most common element on the Earth, may be found
in minor quantities in most water supplies. It seldom exceeds 10 ppm in
drinking water and usually is less than 2 ppm. In some brine or runoff in
agricultural areas the potassium concentration may reach 100 ppm.
APPLICATION:
Drinking, surface, and saline water.
RANGE: 0.0 – 10.0 ppm Potassium
METHOD: Potassium reacts with sodium tetraphenylborate to form a
colloidal white precipitate in quantities proportional to the
potassium concentration.
SAMPLE
HANDLING &
PRESERVATION: Store samples in polyethylene bottles, not in soft glass where
leaching of potassium from the glass may occur. Samples may
be acidified to pH 2 with nitric acid, but should be
neutralized before analyzing.
INTERFERENCE: Calcium and magnesium interfere at very high
concentrations. Check for stray light interference (see page
17).
COD PLUS TEST PROCEDURES 6/02 POTASSIUM 1/2