Automatic Kjeldahl Nitrogen Analyzer for Sample Protein Handling Precautions
Fully automatic Kjeldahl analyzer is a widely used measuring instrument for the determination of crude protein such as food, grain and oil. It has high operability, safety and accuracy. Welcome to the industry. In order to ensure the accuracy of the instrument's measurement results, in addition to the use of the instrument to fully understand the performance of the instrument, familiar with the operating instructions, the operation in strict accordance with the requirements of the operation, but also need to pay special attention to some operational considerations. The following is a detailed description of the precautions for the determination of sample protein in the fully automated Kjeldahl analyzer . 1 The reagent solution used is prepared by using ammonia-free distilled water; 2 sampling should be representative, fully mix the sample before sampling; 3 When weighing the sample into the Kjeldahl flask, do not allow the sample to adhere to the neck of the bottleneck to avoid nitrogen loss caused by the sample being completely digested; 4 In order to ensure complete digestion of the residue on the wall of the flask, the Kjeldahl flask is rotated from time to time during the digestion process; 5 When digesting samples with high fat or sugar content, it is easy to produce a large amount of foam. To prevent foam overflow, digest should be digested and heated and shaken continuously, or a small amount of octanol or liquid paraffin or silicone oil defoamer should be added; 6 When the sample digestive juice is cloudy or unclear and transparent, the Kjeldahl flask can be cooled to room temperature, then 30% hydrogen peroxide is added, and then heated and digested; 7 After adding alkali, the funnel should be sealed with water to avoid the accuracy of the result of ammonia leakage caused by leakage of the device; 8 to ensure that the distillation unit can not leak; 9 The difference in pressure between the reaction chamber and the outside during distillation, the steam can carry out the ammonia. Therefore, when distilling, ensure that the steam is even and sufficient, and the heating cannot be stopped in the middle to prevent back suction; 10 If the digestive solution is blue before the addition of alkali, no copper hydroxide precipitate is formed after the addition of alkali, indicating that the amount of alkali added is insufficient, and an appropriate amount of alkali is needed; and in order to prevent liquid boiling in the steam generator during distillation, a few pieces are added. Broken porcelain or large glass beads, the diameter of the glass beads is preferably larger than the diameter of the glass tube of Unicom, so as to prevent the glass beads from entering the glass tube to affect the uniform and sufficient output of the steam; the lower end of the condensation tube should be inserted below the liquid level of the boric acid absorption liquid to prevent ammonia escaping. After the distillation is completed, the lower end of the condensation tube is lifted off the liquid surface, and after steaming for 1 minute, the nozzle is cleaned, then the absorption bottle is removed, and finally the heat source is turned off, otherwise reverse suction may occur. hand sewing Decorative pendant NINGBO JINCHEN CRAFTS GIFTS CO.LT , https://www.jinchenlovecrafts.com