Application of TFC series soil nutrient tester VI- reagent reagent preparation method

(The reagent preparation in this reagent box is entirely derived from the national standard "Agrochemical Analysis Method")

01: phenol solution: Weigh 13.5 g of sodium hydroxide, 1.5 g of EDTA disodium salt, 2.5 g of sodium acetate, dissolve in about 200 ml of distilled water, add 22.5 g of phenol, dissolve and add distilled water to 500 ml. Brown bottles are kept in a cool place.

02: Sodium hypochlorite solution: Take 100ml of sodium hypochlorite with 5.25ml of the measuring tube and mix with 400ml distilled water. Store in a cool, brown bottle.

03: 4ppm, 8ppm ammonium nitrogen standard solution: (1) Weigh 0.4717g of anhydrous ammonium sulfate in distilled water, add 2ml of concentrated sulfuric acid, and add water to a volume of 1000ml. This liquid is a 100ppm standard solution. (2) Use a graduated pipette to draw 2 ml of 100 ppm standard solution and 4 ml respectively into a 50 ml volumetric flask. Distill with distilled water, the corresponding content is 4 ppm and 8 ppm.

04: Molybdenum sulphate solution: 126 ml of concentrated sulfuric acid was slowly added to a beaker containing 400 ml of distilled water, and stirring was continued, and cooling was performed. Another 10 g of ammonium molybdate was dissolved in a beaker containing 300 ml of distilled water and cooled. Weigh 0.5 grams of bismuth potassium tartrate in a beaker containing 100 ml of distilled water; slowly pour the sulfuric acid solution into the ammonium molybdate solution; pour the potassium antimony tartrate solution into a volume of 1 litre and store it in a brown bottle. in.

05:1ppm effective phosphorus standard solution: (1) Weigh 0.4390 grams of high-quality pure potassium dihydrogen phosphate dissolved in distilled water, add 2 ml of concentrated sulfuric acid, add water to volume to 1000 ml, this liquid is 100ppm standard solution. (2) Using a graduated pipette, draw 1 ml of the 100 ppm standard solution into a 100 ml volumetric flask and dilute to volume with distilled water. The content is 1 ppm.

06: Thymolphthalein solution: Weigh 0.05 g of thymolphthalein into 50 ml of 95% ethanol.

07: EDTA solution: Dissolve 10 g EDTA disodium salt in 100 ml of distilled water, add 5 drops of thymolphthalein solution, and then add sodium hydroxide solution to light blue, and store in a brown bottle.

08: sodium tetraphenylboron solution: 6 g of disodium hydrogen phosphate and 6 g of sodium tetraphenylborate are weighed, dissolved in 200 ml of distilled water, left overnight, and filtered in a brown bottle the next day.

09: Formaldehyde solution: Measure 100 ml of formaldehyde containing 37% reagent, add 5 drops of thymolphthalein solution, light blue with 8% sodium hydroxide solution, and store in a brown bottle.

10:20ppm available potassium standard solution: (1) Weigh 0.1907 g of high-quality pure potassium chloride dissolved in distilled water, add 2 ml of concentrated sulfuric acid, and add water to a volume of 1000 ml. This liquid is a 100 ppm standard solution. (2) Using a graduated pipette, draw 20 ml of 100 ppm standard solution into a 100 ml volumetric flask and dilute to volume with distilled water. The content is 20 ppm.

11: concentrated sulfuric acid: 98% (analytically pure). (Please bring your own)

12: Potassium dichromate solution: Weigh 39.23 grams of potassium dichromate (analytically pure), dissolve in 600 ml of water, dissolve and dilute to 1 litre with distilled water.

13: 0.5%-C standard solution: Weigh 1.376 g of glucose (chemically pure) in a 100 ml volumetric flask. After dissolving it with distilled water, add 1 ml of concentrated sulfuric acid. Add water to volume and shake. The standard solution contains carbon. 5 mg/ml.

14: Potassium chloride: 15 g (Analytical Pure).

15: Sodium bicarbonate: 8.4 g (Analytical Pure).

16: Sodium Nitrate: 17 g (Analytical Pure).

17: Ascorbic acid: 8 g (analytically pure).

18: Citric acid: 4 g (analytically pure).

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