Hanna Instruments HI 83200C User Manual

Page 58

114

115

Silica

SILICA

SPECIFICATIONS

Range

0.00 to 2.00 mg/L

Resolution

0.01 mg/L

Accuracy

±0.03 mg/L ±3% of reading at 25 °C

Typical EMC

±0.01 mg/L

Deviation
Light Source

Tungsten lamp with narrow band interference filter @ 610 nm

Method

Adaptation of the

ASTM Manual of Water and Environmental Technology, D859,

Heteropoly Blue method. The reaction between silica and reagents causes a blue tint in
the sample.

REQUIRED REAGENTS

Code

Description

Quantity

HI 93705

A-0

Molybdate

6 drops

HI 93705

B-0

Citric acid

1 packet

HI 93705

C-0

Amino acid

1 packet

REAGENT SETS

HI 93705-01 Reagents for 100 tests
HI 93705-03 Reagents for 300 tests
For other accessories see page 128.

MEASUREMENT PROCEDURE

• Select the

Silica method using the procedure described in the

Method Selection section (see page 12).

• Fill the cuvette with 10 mL of unreacted sample (up to the

mark).

• Add 6 drops of HI 93705A-0 Molybdate reagent. Replace the

cap and swirl the solution.

• Wait for 4 minutes, add the content of one packet of HI 93705B-0

Citric acid reagent and shake until it is completely dissolved.

• Wait for 1 minute. This is the blank.

• 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 ▲ or ▼ to access the second level functions.
• Press the

Chem Frm key to convert the result in mg/L of potassium oxide (K

O).

• Press ▲ or ▼ to return to the measurement screen.

INTERFERENCES

Interferences may be caused by:
Ammonium above 10 ppm
Calcium above 10000 ppm as CaCO

Chloride above 12000 ppm
Magnesium above 8000 ppm as CaCO

Sodium above 8000 ppm

Potassium LR

1’

10 mL