YOKOGAWA UV700G, User Manual

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<5. Calibration>
5-15
IM 12K01B02-01E
5.5 TURB (turbidity) Span Calibration
Only the span calibration is applied to the calibration method for TURB.
Perform TURB span calibration after performing the common zero calibration and the common
span calibration of UV/VIS.
Refer to “5.1 Calibration Pattern and its cycle”.
TURB span calibration is to obtain the turbidity coefficient converted from the light absorption of
VIS.
The rough standard of the TURB measuring range is approximately 200 deg. by kaolin
concentration.
5.5.1 How to Prepare the Calibration Solution
l
<Reference> How to Prepare the TURB Span Calibration Solution
• Polystyrene latex (PSL) standard solution (100 deg.)
Adjust the calibration solution using the commercially available turbidity standard solution of
polystyrene latex (100 deg.).
NOTE
If using the calubration solution just after compounding it, air bubbles may affect the readings.
Stable calibration requires some time after compounding.
• Kaolin standard solution
Refer to JIS K 0101.
1. Purified kaolin
Sample Quantity JIS
Kaolin clay — Approximately 10 g
Sodium diphosphate decahydrate JIS K 8785
0.2 g
Formaldehyde JIS K 8872 Approximately 10 mL
Put approximately 10 g of kaolin clay into the 500 mL beaker, add the 300 mL of water and
0.2 g of sodium diphosphate decahydrate designated by JIS K 8785, and stir hard using the
magnetic stirrer for approximately 3 minutes. Pour the solution into the 1000 mL measuring
cylinder (lid is available), add the water to the 1000 mL gauge line, put on the lid, and stir
hard for approximately 1 minute. After leaving the solution at rest for 1 hour in ambient
temperature, discard 250 mL of the solution from the top using a siphon, and obtain another
250 mL of solution.
Centrifuge the solution in 3000 min
-1
(adjusting the rotating speed according to the semi
diameter of the rotary part of the centrifugal separator) for 20 minutes, or filter using a filter
with a pore diameter of under 1 µm.
Heat the filtered kaolin at a temperature of 105 °C to 110 °C for approximately 3 hours,
stand to cool in the desiccators, and keep the solution in a wide-mouth bottle.
cool in the desiccators, and keep the solution in a wide-mouth bottle.
2. Concentrated kaolin standards solution (1000 deg.)
Take 1.00 g of the purified kaolin to disperse in a moderate amount of water, and pour
the full dosage of kaolin standard solution into the 1000 mL flask. Then, after adding
approximately 800 mL of pure water and approximately 10 mL of formaldehyde designated
by JIS K 8872, add pure water up to the gauge line.