Identification method of feed grade dicalcium phosphate

As a feed additive, dicalcium phosphate (DCP) mainly provides phosphorus, calcium and other mineral nutrients for livestock and poultry compound feed, which is easy to digest and absorb. It can accelerate the growth and development of livestock and poultry, shorten the fattening period, and gain weight rapidly; it can improve the breeding rate and survival rate of livestock and poultry. At the same time, it can enhance the disease resistance and cold tolerance of livestock and poultry, and has a preventive effect on osteochondrosis, pullorum and paralysis. With the development of the breeding industry, the demand is increasing, and counterfeit and shoddy products are also flooding into the market, which brings great economic losses to the poultry and animal husbandry industry.

Common dicalcium phosphate adulterants include: stone powder, bone meal, agricultural superphosphate, tricalcium phosphate, talc, phosphate rock powder and phosphoric acid mixture, and stone powder and phosphoric acid mixture. Some of these adulterated products contain high calcium and phosphorus, but the utilization rate of livestock and poultry is very low. Some contain a large amount of fluorine, which seriously endangers the health of livestock and poultry. The following introduces the identification and testing method of dicalcium phosphate for your reference.

1. Appearance: 

Feed grade dicalcium phosphate is white powder with uniform fineness. The color of dicalcium phosphate mixed with bone meal is grayish or yellowish brown, and it has the smell of bone meal.

2. Test for phosphate ions:

A small amount of sample is wetted with 5% silver nitrate solution and turns yellow, indicating the presence of phosphate ions. If there is no such change, it means that this sample is not dicalcium phosphate.

3. Calcium ion test

Weigh 0.1g of sample, add 5ml of glacial acetic acid, boil and cool, filter, add 5ml of 3% ammonium oxalate solution to the filtrate, if a white precipitate is formed, it means that calcium ions exist.

4. Dissolution test

Take a small amount of sample, add salt to dissolve, if there is violent bubbling, gas will be generated, put 0.3% calcium hydroxide solution through it, if white precipitate occurs, the sample is mixed with calcium raw materials such as stone powder. If it is completely insoluble, the sample may be phosphate rock powder, talc powder, etc. If a small amount is dissolved, the sample may be superphosphate or the like.

5. Determination of phosphorus content

In an acidic medium, phosphate and quinoline molybdate in the sample solution form a precipitate of quinoline phosphomolybdate. The precipitate was filtered, washed, dried at 180°C, and weighed to calculate the phosphorus content. The Chinese feed standard stipulates that the phosphorus content is ≥16.0%, and the normal content range is 16.00%-18.0%. If it is not within this range, it is an adulterated product.

6. Determination of calcium content

Add an excess of disodium EDTA solution to the sample solution to complex with calcium ions. Using chrome black T as an indicator, titrate the excess disodium EDTA with zinc standard solution to calculate the calcium content. The Chinese feed standard stipulates that the calcium content is greater than or equal to 21.0%-23.3%. If it is not within this range, it is a fake product.

7. Determination of fluorine content

Fluorine is a trace element necessary for the normal physiological activities of animals, but it is also a toxic element. Long-term ingestion of feed containing excessive fluorine in livestock and poultry will cause chronic fluorosis and seriously affect the normal growth of livestock and poultry. Therefore, fluorine in dicalcium phosphate must be detected. The detection of fluorine generally adopts the fluoride ion-selective electrode method. The Chinese feed standard stipulates that the fluorine content in feed-grade dicalcium phosphate should not exceed 1800mg/kg. If the measured result exceeds the standard, it is an adulterated or non-detoxified product and cannot be used.

It is hoped that the above identification and inspection methods can help farmers and feed mills avoid purchasing counterfeit dicalcium phosphate. Polifar is a professional feed additive distributor, we are committed to providing customers with quality products, and product safety is our priority. If you need feed additive products, please contact us!