Calibrating Color - horiba TW-150 Instruction Manual

4.5

Calibrating Color

There are three calibration patterns for color, not including automatic zero calibration.
See "4.1 Calibration Patterns and Cycles" (page 17) and select one of the patterns.
See "5.3 Automatic Zero Calibration" (page 82) for automatic zero calibration settings.
Note
Span calibration solution for color affects the residual-chlorine sensor. When performing span
calibration for color, remove the residual-chlorine sensor and attach the provided rubber plug.
Tip
Turbidity may cause variation in the measured value of color. Correct turbidity as required.
See "5.10.3 Correcting color using turbidity" (page 102).
<Reference> Making color span calibration solution

CHEMICAL CAUTION
Be careful not to drop color span calibration solution on your skin or drink it.
If color span calibration solution comes into contact with your skin or eyes, immediately wash away
with running water. If you swallow the solution, contact your doctor immediately.
Color standard solution (500 PtCo)
Referring to ASTM D1209
Take 1.245 g kalium hexachloro-platinate (IV) (potassium chloroplatinate) and 1.00 g of cobalt
(II) chloride hexahydrate, add them to 100 mL of hydrochloric acid. Dissolve it with purified
water, pour it into a 1000 mL flask, and then fill it with purified water up to the gauge line. Store
the liquid in a colored bottle.
Color standard solution (20 PtCo)
Put 40 mL of commercial color standard solution (500 PtCo) or solution prepared using the
above procedure into a 1000 mL flask and fill it with purified water up to the gauge line.
Note
This instrument is calibrated with the span calibration standard solution described above page 31
before sending for shipping inspection. Depending on the turbidity of the sample, measurement result
may deviate from the TCU* manually analyzed value if default factory setting is used. Refer to page
166 for more information about the procedure for TCU unit conversion.
*: TCU (True Color Unit): "True chromaticity" which is obtained by measuring the chromaticity after
filtration.
Reagent
Kalium hexachloro-platinate (IV)
Cobalt (II) chloride hexahydrate
Hydrochloric acid
CAUTION
Amount
1.245 g
1.00 g
100 mL
4 CALIBRATION
31