This standard specifies the determination method of dehydroacetic acid in fruit juice, fermented bean curd and pickles. This standard is applicable to the determination of dehydroacetic acid content in fruit juice, fermented bean curd and pickles. The detection limit of this standard is 2.0 mg/kg for juice, 8.0 mg/kg for fermented bean curd and pickles. GB/T 5009.121-2003 Determination of dehydroacetic acid in food GB/T5009.121-2003 Standard download decompression password: www.bzxz.net

ICS.67,040
National Standard of the People's Republic of China
GB/T5009.121—2003wwW.bzxz.Net
Substitute GB/T1494-1394
Detertninatinn of dehydroacetic acld in fonds2003-08-11Promulgated
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implemented on 2004-01-01
GE/T5009.121—2003
This standard recommends GB/T14941—1394Determination of dehydroacetic acid in foods. Compared with (B/T14947--1994), the main changes of this standard are as follows: the Chinese name of the standard has been changed, and the standard is called deoxygenation in food. The limit of deoxygenation in food is determined according to GB/T20001.4-2001 Standard Compilation Rules Part 4: Chemical Analysis Methods 3. The conclusions of the original standard have been revised. This standard is proposed by the Ministry of Health of the People's Republic of China, and the drafting units of this standard are: Food Safety Inspection Station of the Ministry of Health, Beijing Municipal Health Commission. The main authors of this standard are Wang Zhutian, Song Fengying, and Gao Hema. The original standard was first issued in 4, and this autumn is the second edition. Scope
Determination of dehydrogenated acetic acid in food
This standard specifies the determination method of dehydrogenated acetic acid in fruit juice, milk and pickles. This standard is applicable to the determination of dehydrogenated acetic acid content in fruit juice, milk and pickles. The detection limit of this standard is 2.0 mg/kg for juice, 8.0 g/kg for milk and pickles.2 Principle
GB/1009.121—2003
After the sample is evaporated, the dehydrogenated acetic acid is extracted with silica gel, concentrated, and separated by gas chromatography with a hydrogen ionization detector, and compared with the standard series for quantification.
3 Reagents
3.1 Evaporation,
3. 2. 3.3. Anhydrous sulfuric acid. 3.4. Addition of 1g/L sodium hydroxide solution. 3.5. 10% (sulfur content > 10%), 3.6. 3.7. Dehydroacetic acid standard mixture, 50% dehydroacetic acid standard solution 3 ml. Dilute in a volumetric flask with vortex to 100, 200, 300, 400, 500, 1.8 g/L dehydrogenation solution per ml, 4.1. Gas chromatography: ionization detector with hydrogen station, 4.2. 5. Analytical step 5. 3 Extraction
The sample was homogenized within 30 minutes and then added to 25 μL of 4-well solution. 1 μL of sodium ion solution was added. The mixture was acidified with 1 μL of 1% ethanol. The mixture was extracted three times with 5 and 30.30 ml of ethanol, respectively, for 8 minutes each time. The surface water was discarded and the mixture was added to 250 ml of acetaldehyde-free milk. The mixture was washed with 10 μL of saturated oxidizing liquid for 10 minutes, and the water layer was discarded. The water in the neck of the funnel was removed with filter paper, and the cotton was inserted. 10 μL of sodium ion solution was added. , wide humidity 3Uui, standard i water lead K concentrator rises to nearly ten, blow high gas to reduce the large residual powder, use acetone to make up the volume.
De-emulsification, pickles: take 5 pre-hybridized test tubes, 100ml of Hong Kong and oxidized solution, continue to adjust the mixture with 0.30% ether (3% commercial ether is vigorously shaken to emulsify) and absorb the aldehyde in 25ml. The liquid needs to be separated and washed with 1ml saturated oxidized solution Let it stand once, remove the woody layer, and adjust the precipitation with 50.50mL of sodium carbonate solution, each time for 2min. Transfer the aqueous layer to the first partition, add hot sodium ions to extract, and add 19% anhydrous acid to 250ml of cotton wool to remove moisture from the leaking part. Place at room temperature for 50min, and concentrate in a 50°C water bath until it is almost dry. Collect and remove the residual 5.2 Chromatographic conditions: 5.2.1 Chromatographic column: glass column, inner diameter 3Trim, length 2.m, 60 mesh ~8o Chrompsorb WAWDMCS, 5% FGS + 1% phosphate (HPQ) stationary phase, column source: 165℃, injection port. Detector temperature 220℃. 5.2.2 Gas flow conditions, number gas 50mL/min, bandwidth gas 500ml/min, oxygen 40mL/min, 5.3 Determination: Inject 2 standard series of concentrations into the spectrometer, determine the peak height of different degrees of dehydrogenated ethyl, with the concentration width as the coordinate and the peak height as the coordinate, and inject 2μ sample at the same time, determine the peak height and compare it with the standard curve for quantitative calibration. 5.4 Calculation of results
Calculate according to the following formula:
mx1000
Wherein!
dehydroacetic acid content in the sample, in g/ml; A——dehydroacetic acid content in the sample to be tested, in g/ml; V——volume of the sample to be tested after settling, in ml; mass of the sample, in g.
The calculation result shall retain two valid digits.
6. Precision
The absolute difference of two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 104
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