In order to solve the manufacturers can analyze the determination of nitrogen and phosphorus in organic fertilizers. The main point of the method is to use a sulfuric acid-hydrogen peroxide digestion sample to prepare the test solution, and determine the nitrogen and phosphorus respectively. Nitrogen measurement can complete the distillation, absorption, and titration of nitrogen in 10 minutes using the Kjeldahl nitrogen analyzer, which has the characteristics of rapid and accurate measurement. Phosphomolybdic acid quinoline weight method for phosphorus measurement. At a temperature of 120°C, the phosphorous precipitates were dried together for 115 hours to determine phosphorus, which greatly shortened the operation time. The Kjeldahl nitrogen determination method is used in production practice and is basically consistent with the results of the analysis methods of national industry standards.
The common compound fertilizer factory can apply this method to determine the content of nitrogen and phosphorus in organic fertilizers without adding analytical instruments to meet the requirements of production guidance. Kjeldahl method principle: Organic fertilizer is heated in sulfuric acid solution, and hydrogen peroxide solution is added dropwise to rapidly digest organic matter, to prepare nitrogen, phosphorus test solution, and then determine nitrogen by using NC-2 rapid determination of nitrogen. Phosphorus was determined by the phosphomolybdic quinoline gravimetric method and potassium by the tetraphenylborate gravimetric method.
Preparation of sample to be measured The sample was weighed in a 250 mL conical flask, 15 mL of concentrated sulfuric acid was added, covered with a short-necked funnel and heated on a low-temperature electric furnace to produce sulfuric acid white smoke for several minutes. After the sample was digested into a black paste, Kjeldahl was stopped. Heat, take a little cold and take out the small funnel. Use a dropper to absorb hydrogen peroxide. Drip it slowly from the wall of the flask until the solution turns from black to colorless. Continue to cover the small funnel and repeat the above operation to completely decompose the organic matter. , Stop adding hydrogen peroxide, continue to heat the solution at low temperature until it takes 15 to 20 minutes of sulfuric acid white smoke, cool, add water to about 75mL, and then cool, transfer the solution into a 100mL volumetric flask, and dilute to volume. The solution was dry filtered and the filtrate was reserved for nitrogen and phosphorus.
Preparation of samples for test liquids This method uses chemical analysis methods for the determination of nitrogen and phosphorus. Compared to Kjeldahl analysis methods, the former requires a relatively large number of samples and has good accuracy, due to the uniform organic fertilizer as a whole. The degree of cross-over, the sample needs less, so the reproducibility of the measurement results appear to be relatively weak, but the Kjeldahl determination of the reproducibility of the test to meet the requirements, while the sample can be measured with the same sample to determine the nitrogen, Phosphorus has the advantages of convenience and speed.
The common compound fertilizer factory can apply this method to determine the content of nitrogen and phosphorus in organic fertilizers without adding analytical instruments to meet the requirements of production guidance. Kjeldahl method principle: Organic fertilizer is heated in sulfuric acid solution, and hydrogen peroxide solution is added dropwise to rapidly digest organic matter, to prepare nitrogen, phosphorus test solution, and then determine nitrogen by using NC-2 rapid determination of nitrogen. Phosphorus was determined by the phosphomolybdic quinoline gravimetric method and potassium by the tetraphenylborate gravimetric method.
Preparation of sample to be measured The sample was weighed in a 250 mL conical flask, 15 mL of concentrated sulfuric acid was added, covered with a short-necked funnel and heated on a low-temperature electric furnace to produce sulfuric acid white smoke for several minutes. After the sample was digested into a black paste, Kjeldahl was stopped. Heat, take a little cold and take out the small funnel. Use a dropper to absorb hydrogen peroxide. Drip it slowly from the wall of the flask until the solution turns from black to colorless. Continue to cover the small funnel and repeat the above operation to completely decompose the organic matter. , Stop adding hydrogen peroxide, continue to heat the solution at low temperature until it takes 15 to 20 minutes of sulfuric acid white smoke, cool, add water to about 75mL, and then cool, transfer the solution into a 100mL volumetric flask, and dilute to volume. The solution was dry filtered and the filtrate was reserved for nitrogen and phosphorus.
Preparation of samples for test liquids This method uses chemical analysis methods for the determination of nitrogen and phosphorus. Compared to Kjeldahl analysis methods, the former requires a relatively large number of samples and has good accuracy, due to the uniform organic fertilizer as a whole. The degree of cross-over, the sample needs less, so the reproducibility of the measurement results appear to be relatively weak, but the Kjeldahl determination of the reproducibility of the test to meet the requirements, while the sample can be measured with the same sample to determine the nitrogen, Phosphorus has the advantages of convenience and speed.
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