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7 Determination of chloride content
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1 Method summary
In an acidic solution of nitric acid, the chloride ions in the sample and silver nitrate generate silver chloride , which is turbidity with the standard turbidity solution
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2 Reagents
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1 Nitric acid solution: 1+2.
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2 Silver nitrate solution: 50g/L
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3 Chloride (Cl) standard solution: 0.
01mg/mL, prepared before use
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3 Apparatus
Visible spectrophotometer with 5cm cuvette
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4 Analysis steps
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1 Preparation of test solution
Weigh 1g laboratory sample, accurate to 0.
1g, add it to a 50mL colorimetric tube, add 2mL nitric acid solution, and then add water to 25mL as the test solution
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2 Preparation of chloride standard turbidity solution
Take different volumes of chloride (CD) standard solutions according to product specifications (see Table 2) into three 50mL colorimetric tubes, add 2mL nitric acid solution to each, and then add water to 25mL as the standard turbidity chloride solution
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Table 2 The volume of chloride (CI) standard solution in the standard turbidity solution of products of different specifications
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3 Visual method
Add 1 mL of silver nitrate solution to each colorimetric tube containing the test solution and the chloride standard turbidity solution , shake it well, and place it in a dark place for 25 minutes.
Perform axial turbidity with the chloride standard turbidity solution corresponding to the corresponding specifications , To determine the level of the indicator
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4 Spectrophotometry (Arbitration Law)
Add 1 mL of silver nitrate solution to each colorimetric tube containing the test solution and the chloride standard turbidity solution , shake it well, and place it in a dark place for 25 minutes, with water as a blank, and measure the absorbance at a wavelength of 420 nm
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Compare the absorbance value of the test solution with the absorbance value of the chloride standard turbidity solution corresponding to the corresponding specification to determine the level of this index
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