horiba TW-100, Instruction Manual

Page: 73 / 175

4 CALIBRATION
61
4.8.2 <Reference> Common zero calibration and span calibration
<residual chlorine>

Preparation

Calibration tank…1

Span standard solution…1 L (Pour the solution into the calibration tank)

Used fluid tank (Install it so that used fluid goes into the tank)

Calibration procedure
Perform calibration in the order: common zero calibration
→
span calibration.

<Reference> Making residual-chlorine span calibration solution

Sodium hypochlorite standard solution
Put 35

L of commercial sodium hypochlorite solution (approximate) into a 1000 mL flask, add
approximately 0.34 g of HORIBA pH 7 standard solution powder (Cat. No. 150-7), and then fill
it with purified water up to the gauge line. Use this solution to determine the residual-chlorine
value according to the procedure in JIS-K0101.
Note

The amount of sodium hypochlorite mentioned above is an approximate amount. Sodium
hypochlorite concentration varies depending on reagent manufacturers and storing conditions.
Adjust the loadings so that the residual chlorine concentration is within 2 mg/L.

Adjust the loadings of potassium chloride and pH adjuster so that the values of the pH and
conductivity in the calibration solution match the sample water. Titrate the calibration solution
based on the iodometric titration flow method in JIS-K0101 and determine residual-chlorine
concentration.
MEASUREMENT screen CALIBRATION screen CL. CAL. screen
See "4.3 Displaying the Calibration Screen" (page 23).
[CAL.] [CL.]
Reagent Approximate amount
Sodium hypochlorite 35

L
HORIBA pH 7 standard solution (No. 150-7) 0.34 g