Method for detecting nitrite in cubilose based on dialysis bag purification technology

[0070] Example 1

[0071] Preparation of standard solutions

[0072] Nitrite standard stock solution (100mg / L, with NO 2 Measure) Accurately weigh 0.1500g of sodium nitrite dried at 110°C-120°C to constant weight, dissolve in water and transfer to a 1000mL volumetric flask, add water to dilute to the mark, and mix well. Accurately measure 1mL100mg / L standard NO 2 , in a 100mL volumetric flask, add ultrapure water to the mark to make a 1mg / L standard stock solution. Pipette 0.2, 0.4, 0.8, 1.2mL of standard stock solutions into 10mL volumetric flasks, add water to make up to the mark, and make a series of standard nitrite solutions with concentrations of 0.02, 0.04, 0.08, 0.1, 0.2mg / L.

[0073] A series of standard solutions are sequentially injected and analyzed according to the chromatographic conditions, and the chromatographic conditions are as follows:

[0074] The chromatographic column is a 4mm×250mm Dionex IonPacTMAS 19 anion column;

[0075] The guard column i

[0085] Example 2

[0086] Weigh 5.00g (accurate to 0.01g) of the test sample and dilute it to 20mL in a 50mL colorimetric tube, ultrasonically extract for 60min, shake once every 10min to keep the solid phase completely separated, and at the same time take a glass centrifuge tube and add 20mL of water stand-by. After the ultrasound was completed, 5 mL of the solution was extracted, placed in a 44 mm dialysis bag and placed in a glass centrifuge tube filled with 20 mL of water, and extracted by ultrasound for 60 min. Take it out and let it stand at room temperature, pick up the dialysis bag, and use the filtrate for later use.

[0087] Take about 15mL of the above-mentioned filtrate, pass it through a 0.22μm aqueous filter membrane syringe filter, RP column, Ag column, and Na column in sequence at a flow rate of 2mL / min, discard 10mL of the initial eluate, collect the eluate, and inject it into the injection bottle The ion chromatography analysis was carried out directly accor

[0093] Example 3

[0094] Spike recovery

[0095] Add a certain amount of sodium nitrite to the negative bird's nest, mix well, make the standard addition content of nitrite in the sample be respectively 0.4mg / kg, 0.8mg / kg and 4mg / kg (the standard addition level is respectively 1 times quantitative limit, 2 times of quantification limit and 3 times of quantification limit) according to the conditions obtained by optimization to measure nitrite average recovery rate and relative standard deviation (n=6), the average recovery rate of sample is at 83.1-99.6%, and relative standard deviation is at 2.98- 10.16%, in line with the detection requirements, the detection results of this method are credible.