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According to the provisions of GB/T3143
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According to the provisions of GB/T4472-1984
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According to the provisions of SH/T0604
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According to the provisions of GB/T6324.
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According to the provisions of GB/T6283-1986
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The water in the sample reacts quantitatively with the iodine in the electrolyte: the reaction formula is:
H 2 O+I 2 +SO 2 →2HI+SO 3
2I-2e→Ⅰ 2
The number of iodine molecules participating in the reaction is equal to the number of water molecules, and the iodine produced by electrolysis is proportional to the amount of electricity consumed.
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1 Coulomb power moisture analyzer: detection sensitivity of 0.
1ug water
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Or other trace moisture analyzers that can meet the analysis requirements can also be used
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2 Glass syringe: 1mL, should be verified when quantified by volume
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3 Reagents
Electrolyte (commercially available reagent) matched with the coulometric moisture meter
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4 Analysis steps
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1 Instrument calibration
A certain amount of pure water should be injected into the electrolytic cell regularly to calibrate the instrument: the relative error between the displayed value of the instrument and the theoretical value should not be greater than 5%
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2 Sample determination
Add electrolyte to adjust the Coulomb Moisture Analyzer to make the electrolytic cell reach an anhydrous state
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Use a glass syringe to inject the sample, and adjust the sample volume according to the water content of the laboratory sample
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After the sample injection is completed, the coulometric titration is performed, and the water quality is directly read on the display of the coulometric coulometric moisture analyzer
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When the injection volume is expressed by the mass of the laboratory sample, it is calculated according to formula (2)
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When the injection volume is expressed by the volume of the laboratory sample, it is calculated according to formula (3)
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5 Result calculation
The mass fraction of water in the sample, the value is expressed in %, calculated according to formula (2) or formula (3):
Where:
m—The value of water quality read from the instrument, in grams (g);
m 1 ―The value of the mass of the syringe and the sample before injection, in grams (g);
m 2 —The value of the mass of the syringe and the sample after the injection, in grams (g);
V 1 —The value of the sample volume in the syringe before injection: the unit is milliliters (mL);
V 2 —The value of the sample volume in the syringe after sample injection, in milliliters (mL);
P 20- The value of the density of the sample at 20 ℃, the unit is grams per milliliter (g/mL)
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Take the arithmetic mean of the tree parallel determination results as the determination result
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The absolute difference between the two parallel determination results is not more than 5% of the arithmetic mean of the two determination values
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