GB/T 5009.26-2003 Determination of N-nitrosamines in foods

This standard specifies the determination method of volatile N-nitrosamines in beer using gas chromatography-thermal energy analyzer (GO-TEA). This standard is applicable to the determination of N-nitrosodimethylamine content in beer. The instrument's minimum detection amount is 0.1ng. When the sample sampling amount is 50g, the concentration volume is 0.5mL, and the injection volume is 10μL, the minimum detection concentration of this method is 0.1μg/kg; when the sample volume is 20g, the concentration volume is 1.0mL, and the injection volume is 5μL, the minimum detection concentration of this method is 1.0μg/kg. GB/T 5009.26-2003 Determination of N-nitrosamines in food GB/T5009.26-2003 Standard download decompression password: www.bzxz.net

ICS 67.040
National Standard of the People's Republic of China
GB/T5009.26——2003
Generation GB/TECC9.25—1926
Determination of N-nitrosamines in food
Issued on August 11, 2003
Ministry of Health of the People's Republic of China
Standardization Administration of China
Implementation on January 1, 2004
/T6009.26—2003
This standard is revised in comparison with GB/T5003.26:1996. The Chinese name of the standard is changed to >-nitrosamines in foods. The standard is summarized in accordance with GB/21001:1-201 Rules for the preparation of standards, Part 1, Chemical analysis methods. This standard is proposed by the Ministry of Health of the People's Republic of China. The School of Public Health, Beijing Medical University and the Institute of Food Industry, Chinese Academy of Medical Sciences are responsible for the preparation of this standard.
This standard was drafted by the Jilin Provincial Health Institute Epidemic Prevention Station. This standard was first issued in 1996 and revised for the second time in 2001. 21
1 Scope
Determination of N-nitrosamines in food
The first method is gas chromatography thermal energy analyzer method
GB/T 5009.26-2003
This standard specifies the determination of volatile N-nitrosamines in food by gas chromatograph-thermal energy analyzer (C-1A). Standard A is applicable to the determination of N-nitrosodimethylamine content in food. The instrument has a minimum output of 2.1nR, the sample volume is 50mL, and the injection volume is 10l. When the sample volume is 50mL, the sample volume is 10l, the reported value of this method is 1.5g/kg; when ... When the volume is 2g and the input volume is 1ml, the detection concentration of this method is 1.xk.
2 Principle
The sample N-amine is subjected to adsorption or low-temperature desorption in air, and then separated by methyl chloride, and then measured by gas phase thermal energy analyzer [H-IFA]. The principle is as follows:
The nitrite separated by gas chromatography is specifically decomposed in a hot chamber to produce a base The group reacts with the fluorine to generate micro-noise. When the excited NO returns to the state, it emits near-infrared light (50) m-2R0Jmr). The near-infrared light generated is photosensitive and can be detected by the photodetector Mnr>. The group is catalytically cracked and cold-mixed or (TR) is used to remove large impurities. The thermal analysis is based on the detection of the group. The group becomes a specific age detector. 3 Reagents
3.1 Dichloroethane is used with a flame: Take 1mml. Use a double-T) concentrator on a water bath to 1mI. There is no positive response in the thermal analysis. If there is a positive response, the band is put into a glass and then evaporated and tested again until negative. 3.2 Oxygen chain solution (mnl/1) Take 10g sodium hydroxide (Na2OH) and dilute it to 1L with water: 3.3 Soil: Ex!iut (Meruk).
3.4 ​​Nitrogen.
3. 5 hydrochloric acid (0. 1 ml/L).
3.B anhydrous sodium sulfate,
3.7 N-nitramine standard stock solution (201ml/L: absorb 10L of N-nitramine standard solution, approximately equivalent to 10 ml. weigh anhydrous ethanol and then weigh it in a 50mL brown container (accurately 0.0001g). weigh anhydrous ethylenediamine, mix and separate to obtain dimethylamine and dipropyl nitramine. , N industry code base Ming La's reserve was, this contact liquid was sealed and packaged in a dark place (one storage, two car efficiency
3.N-sub-susceptible standard working solution (203M/1): aspirate. Inject N-sub-susceptible standard solution 100μL. Place in a 10m:L brown plate bottle, dilute with water and ethanol to make up the volume, and soak the groove. This liquid needs to be packaged in a new way and then cooled (4), and the blue month is effective 4 devices
4, 1 color language discussion.
4.2 Thermal analysis only.
4.3 Glass layer folded column: 8mm light 4 length
4.4 Decompression steaming device.
4.5KD Concentrator:
GB/T 5009.26--2DC3
4.6 Constant mixing water bath:
5 Analysis steps
5.1 Extraction
5.1.1 Method A, Adsorption with calcined soil
Weigh 20ng of pre-decarbonized sample into a 50L beaker, add 100mL sodium hydroxide (1 mL/min) and 1ml N-iodine-propylene glycol internal standard (20Cg/ml), mix and set aside, put 13Ex.reiu into the coal chromatography column, and knock it down by hand. Put the alcohol sample into the mass. After 1 cm~1=min, wash it directly with 5ml of monochlorobenzene, 5.1, 2. Method 2: Vacuum low-pressure smoke
5.1.2. Add 50.09 mL of the sample and the oxidized sample to a double-necked flask, 41.4% of the residual liquid ([mal/L), and then steam it at 3.3 kPa vacuum. When the sample is left with about 1 mL, adjust the pressure to 3.3 kPa until the sample is almost dry. 5.1.2.2 Transfer the obtained liquid into 20 mL of dichloroethane, add 1 mL of hydrochloric acid (0.1 mol/L). Take 3 times with 20 mL of dichloroethane for 3 minutes each time, and extract the extract. Dehydrate with 10 mL of sodium thiosulfate, 5.2 Concentrate
Transfer the dichloroethane extract to a KD concentrator, add the extract to 10 mL in a 5 °C water bath, and then blow it to 1.4 mL~1. TuL, standby.
5.3 Sample determination
5.3.1 Gas chromatography conditions
5.3.1.1 Gasification temperature, 2℃
5.3.1.2 Chromatography column temperature: 17F, heated to 275℃ at a speed of 75℃/min, then held. 5.3.1.3 Chromatography column: inner diameter 2mm--3u. Length 2m--3m glass column or non-lubricated column, the inside is coated with a fixed relative mass fraction of 10%. 20mol/l of fluorine oxide (1ug/L) or Carhwax 20M/TA with a mass fraction of 13%. 5.3.1.4 Cut gas, flow trace 2ml/in~4ml/min5.3.2 Thermal energy analyzer specifications
5.3.2.1 Filling temperature: 250
5.3.2.2 Pyrolysis temperature, 500,
5.3.2.3 Vacuum: 13Fa-~266Pa
5.3.2.4 Cooling: Use liquid chlorine to cool 150 (CTR exhauster can be used instead. 5.3.3 Determination
Please weakly inject the sample concentration box wave and N-nitrosodimethylamine standard into 5L--10L, use the timer to qualitatively, trend or peak disease to quantitatively.
6 Calculation
The content of N-nitrosodimethylamine in the sample is calculated according to formula 1), XhiVNexV/(hx,xm)||t t||N-the content of sample, in micrograms per gram (g/kg);X
peak quotient of concentrated sample (na
standard working volume V-nitrite vertical production (mm); sample concentration volume, in microliters (/); sample concentration volume, in microliters (u1!V); standard sample concentration volume, in microliters (L); sample mass, in grams (g);
calculated and expressed to two significant figures
7 precision mouse
under repeated inspection conditions, the absolute difference between two independent determination results shall not exceed 16%; Method Gas chromatography-mass addition method
B Scope
GB/T5009.26—2003
This method specifies the determination of N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosopyrrolidine in alcoholic beverages, meat and meat products, vegetables, bean products, bean leaves and other foods. This method is applicable to the determination of N-nitrosodimethylamine, N-nitrosodimethylamine, N-nitrosodimethylamine, N-nitrosodimethylamine and N-nitrosodimethylamine in alcoholic beverages, meat and meat products, vegetables, bean products, condiments, tea and other foods. 9 Principle
The N-nitroso compounds in the sample are extracted with hydrothermal gasification and organic solvent to a certain amount, and then confirmed and quantified by high-resolution peak matching method using gas chromatography-mass addition method. 10 Trial production
10.1. The alkane should be evaporated by full glass flame. 10.2. Anhydrous sodium sulfate.
10.3. Sodium chloride: high purity.
10.4. Acid (1+3).
10.5. Sodium iodide (120g).
10.6. N-nitrosodimethylamine standard solution: use methane as a solvent to prepare standard solutions of N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodipropylamine, and N-nitrosopyrrolidone, so that each milliliter is equivalent to 0.5mg N-nitrosodimethylamine. 10.7. N-nitrosodimethylamine standard solution: add appropriate amount of methane to a 4-10ml volumetric flask, use a micro syringe to absorb 100L of N-nitrosodimethylamine standard solution, weigh it in the above volumetric flasks, and dilute it to the mark with difluoromethane. This rate is applied per ml respectively when srg-V-nitrosamine:
IC.B Refractory brick particles: crush the refractory, attack the 1mm~2mm particles, wash them with ethanol and dichloromethane respectively, burn them in 100% ethanol for 1h as zeolite t1 Instrument
11.1 Steam type amplification device: as shown in the figure. 213
GB/T5009.26—2003
Add Glu
2X>ml. Water gas generator:
1ml or through collection,
Ling Yi Jie
11.7KD energy compressor
Gas chromatography-mass spectrometry instrument.
12 Analysis Steps
12. Water Rectification
1 Water Vapor Distillation
2)) R crush (or shred, powder) the sample, add water directly into the steam circulation bottle (liquid sample is heavier than water curtain steam foil) (the sample is not water) and add chlorinated chloride in the steam circulation bottle to make it fully reacted. Connect the atomizer bottle with water vapor generator and condenser, close it, add 40mL dioxymethylene and a small amount of ice cubes into the conical receiving bottle. Collect a total of 432 ml. Enhanced liquid
12.2 Purification
Add 80g sodium chloride and 3mL sulfuric acid (13) into the chain receiving bottle. Let the oxygen completely decompose: then transfer to a 530ml separatory bucket, plate for 5m. Let stand for stratification. Draw the dioxane into a cone, then use 12cmL distilled water to extract the total, combine and transfer the collected liquid again, the total volume is 160ml. For samples containing high concentration of acyl, such as dyeing wine, preparation language, etc., use 50L sodium sulfate (: column) 2. Wash the organic room twice to remove acetyl.
12.3 Concentration tank
After dehydrating the organic product with water and acid, transfer it to KD concentration tank, add a grain of special food, and concentrate it to 1 ral in a 50℃ bath.
12.4 Gas chromatography-mass spectrometry conditions
12.4.1 Negative spectrum conditions
12.4.1.1 Band temperature: 190°C.
12.4.1.2 Color temperature: N-(N-butyl)-dioxadiamine, N-(N-nitro)diethyl-N-(N-butyl)-dioxadiamine, N-(N-butyl)-dioxadiamine, N-(N-butyl)-dioxadiamine, N-(N-butyl)-dioxadiamine, N-butyl)-dioxadiamine, 214 pyrrolidine, respectively
CB/T 5009.26—2003
3014513c150www.bzxz.net
12.4.1.3 Chromatography, inner diameter 1.8mu~3.）)-mmn. 2m long glass potential, inner forbidden hope with two-way splitter as 15 head PEG2M fixed teaching and hope potassium oxide box liquid <10s/1 60--100 days C romoso: bAwwCs12.4.1.4 Carrier gas: oxygen, flow rate is 40mL/n, 12.4.2 Mass Flow Conditions
12.4.2.1 Resolution:
12.4.2.2 High Ionization Electron: 7″V.
12.4.2.3 Ionization Current: 0,
Ion Source Temperature: 1 80%
12.4.2.5 Ion source charge: 1.33×10*P12.4.2.6 Interface temperature: 180℃.
12.4.3 The determination was carried out by using the high-resolution ionization method with a low-attenuation source, using the fragments of the gold pool (FK) (their mass-to-charge ratios are 68.995, 27.99.9936, 135.932 (0.9526) to monitor the N-nitrosoamine, N-nitrodiamine, A1-boron diamine and 1-phosphono-1-pyrrolidone respectively: their mass-to-charge ratios are 71.0430, 102.075, 33.1106, 100.083) and their retention times for qualitative analysis, and the whole height of the ions on the oscilloscope for quantitative analysis. 13 Calculation of
The content of a certain N-oxide compound in the sample is calculated according to test (2), Xt/R: ×c9526) respectively monitor the N-nitrosoamine, N-nitrodiamine, A1 boron diamine and 1-phosphonopyrrolidone: their mass-to-charge ratios are 71.0430, 102.07S3.: 33.1106, 100.083) and their retention time is used for qualitative analysis, and the whole height of the ion on the oscilloscope is used for quantitative analysis. 13 Calculation of the content of a certain N-nitrosoamine compound in the sample is calculated according to the method (2), Xt/R: ×c9526) respectively monitor the N-nitrosoamine, N-nitrodiamine, A1 boron diamine and 1-phosphonopyrrolidone: their mass-to-charge ratios are 71.0430, 102.07S3.: 33.1106, 100.083) and their retention time is used for qualitative analysis, and the whole height of the ion on the oscilloscope is used for quantitative analysis. 13 Calculation of the content of a certain N-nitrosoamine compound in the sample is calculated according to the method (2), Xt/R: ×c
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