Turbidity Calibration - horiba TW-150 Instruction Manual

4 CALIBRATION
4.6

Turbidity Calibration

There are three calibrating patterns for turbidity, 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.
<Reference> Preparing the standard solutions (10 NTU)
1. Weigh out 5.0 g of hydrazine sulfate (commercial special grade or above), and
dissolve it in 400 mL of deionized water. Dissolve 50 g of hexamethylene tetramine
(commercial special grade or above) in 400 mL of deionized water in another flask.
2. Mix the two solutions and add deionized water until the total solution volume is
1000 mL, and mix well. Store this solution at a temperature of 25C ±3C for 48
hours. The turbidity value (TURB) of this solution is equivalent to 4000 NTU.
3. Dilute 4000 NTU-solution 400 times (use a pipette to measure 2.5 mL of the 4000
NTU solution and pour it into a 1000 mL measuring flask, and fill up to 1000 mL
meniscus). The turbidity value (TURB) of this solution is equivalent to 10 NTU.
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