LaMotte SMART3 Colorimeter - Manual (Page 269)

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 an * are considered to be potential health
hazards. To view or print a Material Safety Data Sheet (MSDS) for these reagents go
to www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail, phone or
fax.
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
MDL: 0.8 ppm
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 acidifi ed 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 p.
69).
SMART3 Test Procedures 2.11 POTASSIUM
Test P
rocedures