Precautions for use of fat analyzer (Soxhlet extractor)

Automatic fat analyzer (Soxhlet extractor) is based on the principle of Soxhlet extraction, which integrates hot soaking, extraction, leaching, solvent recovery and drying to extract and separate organic substances such as fat. So what are the key points to pay attention to when using the fat meter?

I. Sample preparation stage

(1) The sample shall be crushed evenly and dried in a drying oven. Weigh a certain amount of sample and directly introduce it into the folded filter paper. Add a layer of absorbent cotton above the sample and compact it to prevent the sample from floating during the experiment.

（2)A. For lowfat samples such as grain and feed, about 2 grams of crushed samples can be directly weighed, accurate to 0.0002 grams. First, insert a layer of absorbent cotton at the bottom of the filter paper cylinder, then transfer the sample into the cylinder, and then cover the sample with absorbent cotton.

B. Weigh about 2g of high grease sample such as oil from the standby sample, pour it into the drying box, put it into the drying oven at 105 ℃ for 30 minutes, pour it into the mortar while it is hot for grinding, after grinding, add a proper amount of degreased fine sand (about 2g) to grind with the sample until the sample is oily (note: the sample should not only be oily, but also not sticky. Have a certain degree of looseness), transfer it into a filter paper cylinder with absorbent cotton at the bottom, dip a little yimi into the absorbent cotton, dip the sample and fat on the mortar, (it is better to clean the mortar with a little yimi) into the filter paper cylinder, and then insert the absorbent cotton into the upper part to press the sample.

(3) Wash the aluminum cup with boiled water until there is no impurity left in the cylinder, put it in a drying oven for about 1 hour (at 105 ℃), take it out and number it, weigh it and move it into a dryer for cooling.

II. Detection phase

(1) The solution added to the aluminum cup should be about 2cm higher than the sample in the filter paper, so as to ensure that the solution can completely penetrate the sample and make it easier to extract the fat completely.

(2) In the soaking stage, the temperature should not be set too high, and the reflux rate should be 120 drops/minute.

(3) Before soaking the sample, it is best to extract it for 20 minutes, wet the sample with solvent first, and then soak it, so as not to float the sample and affect the results.

(4) The temperature of experimental condensate should not exceed 24 ℃.

III. End of the experiment

(1) Clean the aluminum cup in time and dry it. Dust-free space for storage.

(2) If the laboratory temperature is below zero in winter, the water in the condenser tube shall be discharged to prevent the glass tube from being frozen.