User Manual

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12
3
6
9
1’
Potassium LR
POTASSIUM LOW RANGE
SPECIFICATIONS
Range 0.0 to 20.0 mg/L
Resolution 0.5 mg/L
Accuracy ±3.0 mg/L ±7% of reading at 25 °C
Typical EMC ±0.5 mg/L
Deviation
Light Source Tungsten lamp with narrow band interference filter @ 610 nm
Method Adaptation of the Turbidimetric Tetraphenylborate method. The reaction between
Potassium and reagents causes turbidity in the sample.
REQUIRED REAGENTS
Code Description Quantity
HI 93750A-0 Potassium Reagent 6 drops
HI 93750B-0 Powder Reagent 1 packet
REAGENT SETS
HI 93750-01 Reagents for 100 tests
HI 93750-03 Reagents for 300 tests
For other accessories see page 128.
MEASUREMENT PROCEDURE
Note: for sample preparation follow the COLORED OR TURBID SAMPLES procedure at page 17.
• Select the Potassium LR method using the procedure
described in the Method Selection section (see page 12).
• Fill the cuvette with 10 mL of sample, up to the mark.
• Add 6 drops of HI 93750A-0 Potassium Reagent,
replace the cap and swirl the solution.
• Place the cuvette into the holder and close the lid.
• Press the Zero key. The display will show “-0.0-” when the meter is zeroed and ready for measurement.
• Remove the cuvette and add the content of one packet of
HI 93750B-0 reagent. Replace the cap and gently mix for
one minute by slowly turning the cuvette upside down.
• Reinsert the cuvette into the instrument.
• Press Timer and the display will show the countdown prior to the
measurement or, alternatively, wait for 2 minutes and press Read.
When the timer ends the meter will perform the reading. The
instrument displays the results in mg/L (ppm) of potassium (K).
• Press s or t to access the second level functions.
• Press the Chem Frm key to convert the result in mg/L of potassium oxide (K
2
O).
• Press s or t to return to the measurement screen.
INTERFERENCES
Interferences may be caused by:
Ammonium above 10 ppm
Calcium above 10000 ppm as CaCO
3
Chloride above 12000 ppm
Magnesium above 8000 ppm as CaCO
3
Sodium above 8000 ppm
Potassium MR
10 mL