Kjeldahl nitrogen analyzer is an instrument designed according to the Kjeldahl nitrogen method for determining the total nitrogen in compounds or mixtures. The items that need to be calibrated before use include blank test, determination of recovery rate, and measurement repeatability of the instrument.

The blank test can check the stability of Kjeldahl analyzer and eliminate the interference of impurity nitrogen. Use sucrose (nitrogen-free) instead of the sample, carry out the blank test according to the measurement steps, measure twice continuously, and the average volume of consumed standard titration solution shall not exceed 0.2mL. The determination of the recovery rate can directly reflect the accuracy of the measurement results of the auto Kjeldahl nitrogen apparatus. Utilizing the characteristics of stable nitrogen content of ammonium salt and no digestion, the recovery rate can be determined simply and quickly. The measurement repeatability of the instrument can verify the reliability of the measurement results and is an essential calibration item. Repeat the test 6 times to reduce the error of the result.

The automatic nitrogen analyzer is one of the commonly used general instruments in the laboratory. Full automatic Kjeldahl nitrogen analyzer is widely used to determine the nitrogen content in seeds, grain, food, dairy products, beverages, feed, soil and other agricultural by-products.