Composite fertilizer nitrogen content detection method

A detection method and compound fertilizer technology, applied in the field of analytical chemistry, can solve the problems of cumbersome steps and high cost, and achieve the effects of avoiding foam accumulation, high accuracy, and obvious changes in the titration end point.

Active Publication Date: 2016-05-04
GUIZHOU RES INST OF CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Aiming at the problems of cumbersome steps and high cost in the existing determination methods, the purpose of the present invention is to provide an economical, reasonable, simple and feasible detection method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The compound fertilizer was dried at 80°C to constant weight, and its moisture content was measured. Weigh another 0.3g of compound fertilizer with a precision electronic balance (the balance is accurate to 0.0001g) and place it in a flask, add 9mL of sulfuric acid with a concentration of 95% by mass, digest at 180°C for 5min, raise the temperature to 350°C and continue digestion for 12min, Lower the temperature to 100°C and heat for 2 minutes, cool to room temperature, add 27mL distilled water, 3 drops of phenolphthalein, and use 0.1mol / L sodium hydroxide to titrate the remaining sulfuric acid in the solution. After the titration, add ethanol 0.8 times the volume of the solution, add Use dimethyl sulfoxide with the same volume as ethanol, use phenolphthalein as indicator, and use 0.5mol / L sodium hydroxide solution to titrate ammonium ions, record the titration volume, and calculate the nitrogen content.

Embodiment 2

[0023] The compound fertilizer was dried at 80°C to constant weight, and its moisture content was measured. Precisely weigh 0.4g of compound fertilizer with a precision electronic balance (the balance is accurate to 0.0001g) and place it in a flask, add 16mL of sulfuric acid with a mass percentage concentration of 96%, digest at 190°C for 4min, increase the temperature to 355°C and continue digestion for 11min, Lower the temperature to 110°C and heat for 2 minutes, cool to room temperature, add 36mL distilled water, 3 drops of phenolphthalein, and use 0.3mol / L sodium hydroxide to titrate the remaining sulfuric acid in the solution. After the titration, add ethanol 0.9 times the volume of the solution, add Use 1.5 times the volume of ethanol in dimethyl sulfoxide, use phenolphthalein as an indicator, and use 0.6 mol / L sodium hydroxide solution to titrate ammonium ions, record the titration volume, and calculate the nitrogen content.

Embodiment 3

[0025] The compound fertilizer was dried at 80°C to constant weight, and its moisture content was measured. Precisely weigh 0.5 g of compound fertilizer with a precision electronic balance (the balance is accurate to 0.0001 g) and place it in a flask, add 25 mL of sulfuric acid with a concentration of 98% by mass, digest at 200°C for 3min, raise the temperature to 360°C and continue digestion for 10min. Heat at 120°C for 1 min, cool to room temperature, add 50 mL of distilled water, 3 drops of phenolphthalein, and use 0.5 mol / L sodium hydroxide to titrate the remaining sulfuric acid in the solution. Dimethyl sulfoxide times the volume of ethanol, using phenolphthalein as an indicator, titrate ammonium ions with 1mol / L sodium hydroxide solution, record the titration volume, and calculate the nitrogen content.

[0026] Total nitrogen content is calculated according to the following formula in above embodiment:

[0027] Total nitrogen content = (C 0 ×V×M 0 ) / m 0 ×(1-W 水 )in,...

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Abstract

The invention relates to a substance content detection method and especially relates to a composite fertilizer nitrogen content detection method and belongs to the field of analytical chemistry. The composite fertilizer nitrogen content detection method comprises drying composite fertilizer until constant weight, crushing the composite fertilizer, carrying out sieving, carrying out drying until constant weight, weighing a desired amount of the composite fertilizer powder, carrying out digestion on the composite fertilizer powder through sulfuric acid, neutralizing the residual sulfuric acid through sodium hydroxide after digestion, adding ethanol and dimethyl sulfoxide into the solution, and carrying out ammonium ion titration through a sodium hydroxide solution in the presence of a phenolphtalein indicator. The method is simple and easy. Compared with the Kjeldahl determination method, the method provided through the invention is free of alkalization distillation, boron absorption and acid titration processes. The method utilizes laboratorial common apparatuses and reagents and has obvious economic benefits.

Description

technical field [0001] The invention relates to a method for detecting the content of material elements, in particular to a method for detecting the nitrogen content of compound fertilizers, and belongs to the field of analytical chemistry. Background technique [0002] In the process of production practice, the nitrogen content of fertilizer is a very important factor. Traditional determination methods include the Kjeldahl method, which requires a special Kjeldahl instrument, and the steps are cumbersome and time-consuming. High-performance liquid chromatography or gas chromatography is often used in the modern determination of nitrogen content. Although the detection speed is fast, the equipment and maintenance costs are expensive, and it is difficult to be widely used in ordinary laboratories and production units. In addition, it also has high requirements for standard products, and the choice of mobile phase and chromatographic column has a great influence on the detect...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N31/16
CPCG01N31/16
Inventor 陈文兴周昌平杨杰陈思帆王瑶田娟
Owner GUIZHOU RES INST OF CHEM IND
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