Automatic Kjeldahl determination of nitrogen content in biogas slurry
The automatic Kjeldahl nitrogen analyzer is widely used for the determination of total nitrogen in solid and liquid materials. The use of different types of nitrogen analyzers has a great influence on the experimental results and related quality evaluation. This article combines the laboratory's actual use requirements for the instrument, and operates in strict accordance with the instrument's calibration procedures. A method for detecting the accuracy and reliability of the instrument's measurement results is introduced.
The specific test procedure of the automatic Kjeldahl nitrogen analyzer is as follows: take 250mL water sample, digested and distilled to obtain distillate, take 25.0mL sample, digested and distilled to obtain the distillate as all the samples, use acid Titration determination. The Kjeldahl nitrogen analyzer used in this laboratory is an automatic Kjeldahl nitrogen determination instrument. After the sample is tested, the acid titration method is selected as the detection method. Sample testing at the same time as reagent blank test. The sample digestion solution was then measured in a Kjeldahl apparatus, and the volume V1 (mL) of the sulfuric acid standard solution was recorded. At the same time, take the reagent blank digestion solution and record the volume V0 (mL) of the sulfuric acid standard solution.
Through the evaluation of the uncertainty of nitrogen content in biogas liquid by automatic Kjeldahl determination of nitrogen, the relative expansion uncertainty with 95% confidence interval was Urel95% of 4.887%. Analyzing the three types of uncertainty, the repeatability of the experiment contributes the most to the uncertainty, which requires us to continuously improve the experimental operation level during the experiment. At the same time, laboratory conditions are strictly monitored to improve the accuracy of laboratory test data.
The specific test procedure of the automatic Kjeldahl nitrogen analyzer is as follows: take 250mL water sample, digested and distilled to obtain distillate, take 25.0mL sample, digested and distilled to obtain the distillate as all the samples, use acid Titration determination. The Kjeldahl nitrogen analyzer used in this laboratory is an automatic Kjeldahl nitrogen determination instrument. After the sample is tested, the acid titration method is selected as the detection method. Sample testing at the same time as reagent blank test. The sample digestion solution was then measured in a Kjeldahl apparatus, and the volume V1 (mL) of the sulfuric acid standard solution was recorded. At the same time, take the reagent blank digestion solution and record the volume V0 (mL) of the sulfuric acid standard solution.
Through the evaluation of the uncertainty of nitrogen content in biogas liquid by automatic Kjeldahl determination of nitrogen, the relative expansion uncertainty with 95% confidence interval was Urel95% of 4.887%. Analyzing the three types of uncertainty, the repeatability of the experiment contributes the most to the uncertainty, which requires us to continuously improve the experimental operation level during the experiment. At the same time, laboratory conditions are strictly monitored to improve the accuracy of laboratory test data.
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