Common calcium hydrogen phosphate adulterants include vermiculite powder, talc powder, bone powder, phosphate rock powder, tricalcium phosphate, a mixture of agricultural superphosphate, phosphoric acid, and a mixture of stone powder and phosphoric acid. Some of these adulterated products contain higher levels of calcium and phosphorus, but the utilization rate of livestock and poultry is low, and it also contains a large amount of fluorine, which seriously endangers the health of livestock and poultry. The detection method of calcium hydrogen phosphate adulteration is:
(1) Appearance identification
Feed grade calcium hydrogen phosphate is a white powder with uniform fineness. Calcium hydrogen phosphate mixed with bone meal is dark or yellowish brown with a bone powder smell o
(2) Detection of phosphate ions
A small amount of the sample was taken and wetted with a 5% silver nitrate solution to confirm the presence of phosphate ions, otherwise the sample was not calcium hydrogen phosphate.
(3) Dissolution test
Take a little sample, add hydrochloric acid to dissolve, such as vigorous bubbling, will produce gas through the 0.3% calcium hydroxide solution (upper layer of clear liquid), if a white precipitate is produced, the sample is mixed with calcium powder and other calcium raw materials; 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 agricultural superphosphate.
(4) Determination of phosphorus content
In an acidic medium, the phosphate in the sample solution forms a quinoline phosphomolybdate precipitate with quinoline molybdate. The precipitate was filtered, washed and dried at 180 ° C to calculate the phosphorus content. The national feed standard stipulates that the normal content of phosphorus ranges from 16.0% to 18%. If it is not within this range, it is adulterated products.
(5) Determination of calcium content
An excess of disodium edetate solution was added to the sample solution, combined with calcium ions, and chrome black t was used as an indicator. An excess of disodium edetate was titrated with a zinc standard solution to calculate the calcium content. The national feed standard stipulates that the normal content of calcium ranges from 21.0% to 23.3%. If it is not within this range, it is a adulterated product.
(6) Determination of fluorine content
Fluorine is a trace element necessary for the normal physiological activities of animals, and it is also a toxic element. Long-term intake of super-standard fluoride in livestock and poultry can cause chronic fluorosis, which seriously affects the normal growth of livestock and poultry, so it is necessary to detect fluoride in calcium hydrogen phosphate. The detection of fluorine generally uses a fluoride ion selective electrode method. The National Feed Standard stipulates that the content of fluorine in feed grade calcium hydrogen phosphate shall not exceed 180 mg/kg. If the measured result exceeds the standard, it is adulterated or not detoxified and must not be used for feeding.
(1) Appearance identification
Feed grade calcium hydrogen phosphate is a white powder with uniform fineness. Calcium hydrogen phosphate mixed with bone meal is dark or yellowish brown with a bone powder smell o
(2) Detection of phosphate ions
A small amount of the sample was taken and wetted with a 5% silver nitrate solution to confirm the presence of phosphate ions, otherwise the sample was not calcium hydrogen phosphate.
(3) Dissolution test
Take a little sample, add hydrochloric acid to dissolve, such as vigorous bubbling, will produce gas through the 0.3% calcium hydroxide solution (upper layer of clear liquid), if a white precipitate is produced, the sample is mixed with calcium powder and other calcium raw materials; 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 agricultural superphosphate.
(4) Determination of phosphorus content
In an acidic medium, the phosphate in the sample solution forms a quinoline phosphomolybdate precipitate with quinoline molybdate. The precipitate was filtered, washed and dried at 180 ° C to calculate the phosphorus content. The national feed standard stipulates that the normal content of phosphorus ranges from 16.0% to 18%. If it is not within this range, it is adulterated products.
(5) Determination of calcium content
An excess of disodium edetate solution was added to the sample solution, combined with calcium ions, and chrome black t was used as an indicator. An excess of disodium edetate was titrated with a zinc standard solution to calculate the calcium content. The national feed standard stipulates that the normal content of calcium ranges from 21.0% to 23.3%. If it is not within this range, it is a adulterated product.
(6) Determination of fluorine content
Fluorine is a trace element necessary for the normal physiological activities of animals, and it is also a toxic element. Long-term intake of super-standard fluoride in livestock and poultry can cause chronic fluorosis, which seriously affects the normal growth of livestock and poultry, so it is necessary to detect fluoride in calcium hydrogen phosphate. The detection of fluorine generally uses a fluoride ion selective electrode method. The National Feed Standard stipulates that the content of fluorine in feed grade calcium hydrogen phosphate shall not exceed 180 mg/kg. If the measured result exceeds the standard, it is adulterated or not detoxified and must not be used for feeding.
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