In this paper, barium chromate spectrophotometry and barium chromate-diphenyl hydrazine spectrophotometry were compared to study sulfate in river water and rainwater.
Under acidic conditions, barium chromate reacts with sulfate to produce barium sulfate precipitate, and chromate ions are replaced at the same time;
Chromic acid reacts with barium sulfate under acidic conditions to generate barite precipitation, and chromate ions are replaced at the same time;
After the complete reaction, sulfate precipitate and excessive barium chromate precipitate were filtered out, and the filtrate containing chromate ions replaced by sulfate ions was yellow.
After full reaction, sulfate precipitation and excess barium chromate precipitation are filtered out, and chromate ions replaced by sulfate ions filter out yellow filtrate.
The first method is to measure the absorbance of chromate at the wavelength of 370nm with water as reference. The method obeys Beer's law at 8- 120μg/mL, the detection limit is 4μg/mL, and the recovery rate is 97%- 1 12%.
Method A: The filtrate was determined by sulfate spectrophotometry with water as reference at the wavelength of 370 nm. In this method, the ear ratio method was used at 8- 120 μ g/mL, the detection limit was 4 μ g/mL, and the recovery rate was 97%- 1 12%.
Methods Diphenyl carbohydrazide solution and dilute hydrochloric acid were dripped into the filtrate to react with chromate, and the filtrate was purple after color development.
Method 2: Diphenyl carbohydrazide solution was added to the filtrate to react with dilute hydrochloric acid and chromium sulfate, and the filtrate was purple after color development.
Then, with water as reference, the absorbance was measured at the wavelength of 545nm. The method conforms to Beer's law in the range of 0-50μg/mL, with the detection limit of 0. 1μg/mL and the recovery rate of 97%- 108%.
Then the absorbance was measured with water as reference at the wavelength of 545 nm. The detection limit was 0.65438 0 μ g/ml and the recovery rate was 97%-65438 008% by ear ratio method at 0-50 μ g/mL.
The correlation between the standard curves of the two methods, the accuracy of the determination of known samples, the stability of river water samples in our school, the determination range, the detection limit and the simplicity of experimental operation are compared and studied in detail, and a conclusion is drawn.
In this paper, the correlation of standard curve, accuracy of known samples, stability of river water samples, determination range, detection limit, experimental and simplification of the two methods are compared and studied in detail, and a conclusion is drawn.