Detection of formaldehyde content in common food

[Detection significance]

Refer to "NY 5172-2002 Non-polluted Food Aquatic Products" for the determination of formaldehyde content in water products, use acetylacetone spectrophotometry to quantitatively analyze formaldehyde in food, and explore the most suitable wavelength for determination according to actual conditions , This method is easy to operate and has high sensitivity

The quantitative analysis of formaldehyde is mainly based on the formation of stable yellow compounds in the buffer solution of acetic acid -ammonium acetate with formaldehyde and acetylacetone .

[Sampling location]

Fish markets, supermarkets and so on

[Experimental reagents and materials]

Squid shreds, abalone slices, tripe, beef louver;

UV-visible spectrophotometer;

Electronic balance;

Water bath;

Multifunctional food processor;

Distillation device: 500mL distillation flask, straight water condenser;

Liquid paraffin

Phosphoric acid solution (10%): Take 10mL of phosphoric acid and dilute to 200mL with water;

Acetylacetone solution: Weigh ammonium acetate 25g, was dissolved in 100mL distilled water, adding acetic acid 3mL and 0.

Formaldehyde standard solution (5ug/mL): Pipette 0.

[experimental method]

1.

Take a solid sample of 10g, add a small amount of water, use a multifunctional food processor to make a homogenate, place it in a distillation flask, add 2.

Take 100g, g of the liquid sample in a distillation flask, and the subsequent treatment is the same as above

2.

Pipette 0, 2mL, 5mL, 10mL of formaldehyde standard solution into 10mL Nessler's colorimetric tube, and add 1mL of acetylacetone solution, mix well, put in boiling water bath for 3min, take out and cool, take blank as control, and measure respectively Determine the maximum absorption wavelength for the absorbance of the solution of 3 concentrations in the wavelength range of 404 ~ 424nm

3.

Accurately pipet 5pymL of formaldehyde standard solution 0, 0.

4.

Pipette 10mL of the sample distillate into a 10mL Nessler colorimetric tube, add 1mL of acetylacetone solution, mix well, place in a boiling water bath for 3min, take out and cool, take the blank as a control, use a 1cm cuvette for colorimetry, and measure the absorbance , Check the calculation result of the standard curve

[Result analysis]

Count the test results and analyze the most formaldehyde content in water and hair products from different sources and the formaldehyde content of different varieties of products