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GB/T 5413.27-1997National food safety standard -- Determination of fatty acids in foods for infants and young children, milk and milk products (English PDF)

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Issued by

Ministry of Health of the People's Republic of China

Level / Type

National · Recommended

Issue date

March 26, 2010

Implementation date

June 1, 2010

Scope

GB/T 5413.27-1997 (National food safety standard -- Determination of fatty acids in foods for infants and young children, milk and milk products) is available as an English-translated PDF.

GB/T 5413.27-1997 — This standard specifies the method for determination of infant foods and dairy products of fatty acids. This standard applies to the determination of infant foods and dairy products of fatty acids, the second method is not suitable for the determination of fatty acids containing entrapped.

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Document preview — GB/T 5413.27-1997

National Standard of the People's Republic of China

ICS: 67.100.01
Classification: C 53;X82
Replacing: GB/T 21676-2008; GB/T 5413.27-1997; GB/T 5413.4-1997

Issued by: Ministry of Health of the People's Republic of China

Foreword
1 Scope
2 Normative references
4 Reagents and materials
5 Apparatus
6 Step, Analysis
6.1 Sample Processing
6.2 Extraction methyl ester
6.3 Reference conditions chromatography
6.4 Determination of the sample solution
7 Expression analysis
7.1 Calculation sample of each fatty acid content
7.3 Sample a fatty acid percentage of total fatty acids (%) was calculated
8 Precision
9 Other
11 Reagents and materials
12 Instruments and equipment
13 Analysis steps
13.1 Sample Preparation
13.2 Fat extraction
13.3 Esterification saponification
13.4 Chromatographic reference conditions
13.5 Determination
14 Analysis results presentation
14.3 Sample of a fatty acid percentage of total fatty acids (%) was calculated
15 Precision
17 Elaidic acid (C18. 1n9t) 0.5 0.9527 0.9570
21 Peanut acid (C20. 0) 0.5 0.9570 0.9609
35 Eicosapentaenoic acid EPA (C20. 5n3) 1.0 0.9557 0.9592

Foreword

This standard replaces GB/T 21676-2008 "milk and dairy products of fatty acids by gas liquid chromatography", GB/T 5413.27-1997 "Infant formula milk powder and DHA, EPA Determination", GB/T 5413.4-1997 "infant formula milk powder and linoleic acid Determination. " this standard compared with the original standards, the main changes are as follows.

- The first law chloride - methanol, methyl esterification method;

- The GB/T 21676-2008, GB/T 5413.27-1997, GB/T 5413.4-1997 merge this standard second method ammonia - ethanol extract Emulated.

Appendix A of this standard is an informative annex.

This standard replaces the standards previously issued as follows.

--GB/T 5413.4-1997;

--GB/T 5413.27-1997;

--GB/T 21676-2008.

National Food Safety Standard Determination of infant foods and dairy products of fatty acids

1 Scope

This standard specifies the method for determination of infant foods and dairy products of fatty acids.

This standard applies to the determination of infant foods and dairy products of fatty acids, the second method is not suitable for the determination of fatty acids containing entrapped.

2 Normative references

The standard file referenced in the application of this standard is essential. For dated references, only the edition date of the note this applies to this standard. For undated references, the latest edition (including any amendments) applies to this standard.

First Fayi chloride - methanol method methyl ester Principle 3 Acetyl chloride is reacted with methanol to give hydrochloric acid - methanol free sample of fat and fatty acid methyl ester and extracted with toluene, the qi Chromatograph testing, external standard separation.

4 Reagents and materials

Unless otherwise indicated, the reagents used in this method were of analytical grade or above specifications, water as a water GB/T 6682 regulations.

4.1 anhydrous sodium carbonate.

4.2 Toluene. chromatography.

4.3 acetyl chloride.

4.4 acetyl chloride in methanol (10% volume fraction). Measure 40 mL of methanol in 100 mL dry beaker, Imbibe 5.0 mL acetyl chloride (4.3) was slowly added dropwise, stirring constantly, cooled and transferred to a 50 mL volumetric flask and dry. Before use with system.

Note. acetyl chloride is an irritant agent to prepare a methanol solution of acetyl chloride should be stirred constantly to prevent splashing, pay attention to protection.

4.5 sodium carbonate solution. Accurately weigh 6 g anhydrous sodium carbonate (4.1) in 100 mL beaker, dissolved in water, and the transfer of water to the 100 mL volumetric flask.

4.6 fatty acid triglyceride standard. Purity >=99%, fatty acid species in Appendix A Table A.1.

4.7 fatty acid triglyceride standard working solution. Press the fatty acid content of each sample to be analyzed and the type of fatty acids in the preparation of appropriate concentration standard Quasi working fluid volume with toluene and were stored at -10 °C following refrigerator, valid for three months.

5 Apparatus

5.1 Balance. a sense of the amount of 0.01 g and 0.1 mg.

5.2 thermostatic water bath.

5.3 Centrifuge. >=5000 rpm rev/min.

5.4 GC with FID detector.

5.5 freeze-drying apparatus.

5.6 nitrogen blowing instrument.

5.7 screw glass (made with Teflon inner pad screw cap). 15 mL.

5.8 centrifuge tube. 50mL.

6 Step, Analysis

6.1 Sample Processing

6.1.1 Sample water content greater than 5%, freeze-dried to a moisture content of less than 5%.

6.1.2 Weigh the sample 0.5 g (accurate to 0.1 mg) in 15 mL screw-dried glass tube (5.7), and 5.0 mL of toluene (4.2).

6.1.3 Weigh anhydrous butter sample 0.2 g (accurate to 0.1 mg) in 15 mL screw-dried glass tube (5.7), and 5.0 mL Toluene (4.2).

6.2 Extraction methyl ester

6.2.1 Preparation of sample measurement solution

10% methanol solution was added acetyl chloride in the sample (6.1.2 or 6.1.3) in 6.0 mL (4.4), after nitrogen filling, tighten the screw cap and shaken After mixing 80 °C ± 1 °C water bath placed 2 h, every 20 min during shaken once removed, after cooling to room temperature water bath. The reaction After the sample was transferred to a 50 mL centrifuge tube, respectively, with 3.0 mL of sodium carbonate solution (4.5) times cleaning glass, combined with sodium carbonate solution (4.5) tube was 50 mL (5.8), mixing 5,000 rev/min centrifuged for about 5 min. The supernatant as the test solution, the gas chromatograph Determination.

6.2.2 Preparation of the standard solution measured

Imbibe fatty acid triglyceride standard working solution (4.7) 0.5 mL to 15 mL screw-cap glass tube (5.7), and 4.5 mL methyl Benzene and other steps with 6.2.1.

6.3 Reference conditions chromatography

Column. 100% fixative two cyanopropyl polysiloxane, 100 m × 0.25 mm, 0.20 µm, or equivalent column.

Carrier gas. nitrogen.

Carrier gas flow rate. 1.0 mL/min.

Inlet temperature. 260 °C.

Split ratio. 30. 1.

Detector temperature. 280 °C.

Oven temperature. initial temperature 140 °C, kept 5 min, to 4 °C/min heating to 240 °C, maintained 15 min.

Injection volume. 1.0 µL.

6.4 Determination of the sample solution

Imbibe fatty acids were 1.0 µL standard assay solution (6.2.2) and sample measurement solution (6.2.1) into the chromatograph, parallel determination times for not less than two, quantitative chromatographic peak area.

7 Expression analysis

7.1 Calculation sample of each fatty acid content

Fatty acid content of each sample according to the formula (1).

stdi

jstdisi ××

FmA

Xi (1)

Where.

X i - fatty acid content of each sample, the unit is milligram per hundred grams (mg/100 g);

Asi - sample measurement solution peak area of each fatty acid;

mstdi-- lessons in preparing standard assay solution (6.2.2) in a standard fatty acid triglyceride standard working solution contained in the Mass, in milligrams (mg);

Fj - each fatty acid triglycerides into fatty acid conversion factor, see Appendix A, Table A.1;

Astdi - Determination of Standard Solution peak area of each fatty acid;

m - mass of the sample, said sample in grams (g).

The arithmetic mean of two under the same condition of independent determination results indicated that the results to three significant figures.

The total fatty acid content of 7.2 sample calculation Content of total fatty acids in the sample according to the formula (2).

sum = iTotalFA XX (2) where.

XTotal FA-- content of total fatty acids in the sample, the unit is milligram per hundred grams (mg/100 g);

Xi - fatty acid content of each sample, the unit is milligram per hundred grams (mg/100 g).

The arithmetic mean of two under the same condition of independent determination results indicated that the results to three significant figures.

7.3 Sample a fatty acid percentage of total fatty acids (%) was calculated

A fatty acid of total fatty acids in the sample percentage (%) Y according to formula (3) Calculated.

TotalFA

XY or 100

jsi

jsi ××

× = sum FA

8 Precision

Two independent determination results under the absolute difference in repeatability condition must not exceed 10% of the arithmetic mean.

9 Other

The limit of detection in Appendix A Table A.1.

The second method ammonia - ethanol extraction method Principle 10 Fat milk and dairy products by the saponification process of generating free fatty acid methyl esterification reaction at boron trifluoride catalyzed by methyl ester of the fatty acid by GC column after separation, hydrogen flame ionization detector and quantified by external standard.

11 Reagents and materials

Unless otherwise indicated, the reagents used in this method were of analytical grade or above specifications, water as a water GB/T 6682 regulations.

11.1 Methanol. chromatographically pure.

11.2 ether.

11.3 petroleum ether. boiling range 30 °C ~ 60 °C.

Ethanol 11.4 (volume fraction >=95%).

11.5 Ammonia (25% volume fraction).

11.6 n-hexane (C6H14). chromatography.

11.7 Peak's amylase (Taka-Diastase). 128 U/mg.

11.8 boron trifluoride in methanol (14% mass fraction).

11.9 saturated sodium chloride solution. 360 g sodium chloride were dissolved in 1.0 L of water, stirring to dissolve, clarify the reserve.

11.10 potassium hydroxide in methanol solution (0.5 mol/L). Weigh 2.8 g of potassium hydroxide, methanol (11.1) was dissolved and diluted to volume 100 mL, and mix.

11.11 Coke sexual gallic acid without methanol solution (10%). A 1.0 g Coke sexual gallic acid was dissolved in 10 mL of methanol formulated as 10% of coke Gallic acid in methanol spare.

11.12 FAME standard substance. purity >=99%, stored at -10 °C refrigerator below, the fatty acid species in Appendix A

Table A.1.

11.13 FAME standard solution. each sample by fatty acids and fatty acid species being analyzed properly formulated its concentration, Normal hexane and stored at -10 °C following refrigerator, valid for three months.

12 Instruments and equipment

12.1 balance. a sense of the amount of 0.1 mg.

12.2 liposuction tube. 100 mL grinding mouth tube with stopper, liposuction tube and dried to constant weight.

12.3 rotary evaporator.

12.4 Centrifuge. >=5000 rpm rev/min.

12.5 constant temperature water bath.

12.6 GC with FID detector.

13 Analysis steps

13.1 Sample Preparation

Samples will be refrigerated beforehand removed from the refrigerator, put to room temperature.

13.1.1 a liquid sample Weigh 10 g (accurate to 0.1 mg) sample was liposuction tube test.

13.1.2 Solid samples

13.1.2.1 Starch-containing sample

Weigh the sample 1.0 g (accurate to 0.1 mg) to liposuction tube (12.2), was added 0.1 g's peak amylase (11.7), was added 10 mL 45 °C ~ 50 °C of water, mixed with nitrogen to exclude air bottle, covered with cork, set within 45 °C ± 1 °C oven for 30 min, take out.

13.1.2.2 No starch sample

Weigh the sample 1.0 g (accurate to 0.1 mg) to liposuction tube (12.2), and 65 °C ± 1 °C water 10 mL sample dissolution, vibration Shake, the sample was completely dispersed.

Added 2 mL of ammonia (11.5) in the sample (13.1.1 and 13.1.2), at 65 °C ± 1 °C water bath placed 15 min, remove Jiggle, cooled to room temperature.

13.1.3 Anhydrous butter

Weigh the sample 0.2 g (accurate to 0.1 mg) in ground-necked flask, 13.3 according to the saponified esterified.

13.2 Fat extraction

Add 10 mL of ethanol (11.4) in the prepared sample, and mix. Diethyl ether was added 25 mL (11.2), stoppered and shaken 1 min. plus Into 25 mL petroleum ether (11.3), stoppered and shaken for 1 min, allowed to stand, layered organic layer was transferred to ground-necked flask. Then add 25 mL of diethyl ether (11.2) and 25 mL petroleum ether (11.3), stoppered and shaken for 1 min, allowed to stand, stratification, the organic layer was transferred to grinding mouth flask, the operation is repeated once again.

The extracts were combined in ground-necked flask with a rotary evaporator to dryness.

13.3 Esterification saponification

Was added to the concentrate (13.2) or anhydrous cream (13.1.3) 1.0 mL Coke sexual gallic acid methanol solution (11.11). Concentrated and dried After addition of 10 mL of methanol solution of potassium hydroxide (11.10) placed on the 80 °C ± 1 °C water bath reflux for 5 min ~ 10 min. Then add 5 mL Methanol solution of boron trifluoride (11.8) and reflux continued for 15 min, cooled to room temperature, the liquid in the flask transferred to a 50 mL centrifuge tube, divided Do not washed with 3 mL saturated sodium chloride solution (11.9) flask three times, combined with saturated sodium chloride solution in a centrifuge tube 50 mL, 10 mL of n Hexane (11.6), after shaking at 5000 r/min centrifugation 5 min, the supernatant was measured as the test solution, gas phase chromatography (12.6).

NOTE. methanol solution of boron trifluoride is highly corrosive reagents, should pay attention to protection.

13.4 Chromatographic reference conditions

Column. 100% fixative two cyanopropyl polysiloxane, 100 m × 0.25 mm, 0.20 µm, or equivalent column.

Carrier gas. nitrogen.

Carrier gas flow rate. 1.0 mL/min.

Inlet temperature. 260 °C.

Split ratio. 30. 1.

Detector temperature. 280 °C.

Oven temperature. initial temperature 140 °C, kept 5 min, to 4 °C/min heating to 240 °C, maintained 15 min.

Injection volume. 1.0 µL.

13.5 Determination

Imbibe fatty acid methyl esters were 1.0 µL standard solution (11.13) and the solution (13.3) into the chromatograph, parallel determination times for not less than two, quantitative chromatographic peak area.

14 Analysis results presentation

Each fatty acid content of the sample calculation 14.1 Fatty acid content of each sample according to the formula (4) Calculated.

stdi

istdisi

FVCA

Where.

Xi - fatty acid content of each sample, the unit is milligram per hundred grams (mg/100 g);

Asi-- sample solution peak area of each fatty acid methyl ester;

Cstdi - FAME standard working solution concentration of each fatty acid methyl ester, in milligrams per milliliter (mg/mL);

V --13.3 added n-hexane volume. in milliliters (mL);

Astdi - working standard solution peak area of each fatty acid methyl ester;

Fi - each fatty acid methyl esters of fatty acids into the conversion factor, see Appendix A, Table A.1;

m - the specimen sample weight in grams (g).

The arithmetic mean of two under the same condition of independent determination results indicated that the results to three significant figures.

The total fatty acid content of 14.2 sample calculation Content of total fatty acids in the sample according to the formula (5) Calculated.

sum = iXX TotalFA (5) where.

XTotal FA-- content of total fatty acids in the sample, the unit is milligram per hundred grams (mg/100 g);

Xi - fatty acid content of each sample, the unit is milligram per hundred grams (mg/100 g);

The arithmetic mean of two under the same condition of independent determination results indicated that the results to three significant figures.

14.3 Sample of a fatty acid percentage of total fatty acids (%) was calculated

A fatty acid of total fatty acids in the sample percentage (%) Y according to formula (6) Calculated.

TotalFA

XY or 100

isi

isi ××

× = sum FA

FAY (6)

15 Precision

Two independent determination results under the absolute difference in repeatability condition must not exceed 15% of the arithmetic mean.

Other 16

The detection limit, see Appendix A in Table A.1.

Appendix A

(Informative)

A typical gas chromatogram of fatty acids and the conversion factor A.1 37 kinds of fatty acids typical pattern standard solution 37 kinds of fatty acids typical standard solution map shown in Figure A.1.

Note. Columns may lead to a variety of different fatty acids of different peak time, the laboratory should be a single standard calibration peak order prevail

Figure A.1 37 kinds of fatty acids typical gas chromatogram of the standard solution

A.2 various types of fatty acids, fatty acid methyl esters or detection limit and fatty acid triglycerides into fatty acid conversion factor list Various types of fatty acids, fatty acid methyl esters or detection limit and fatty acid triglycerides into fatty acid conversion factor checklist Table A.1.

Table A.1 various types of fatty acids, fatty acid methyl esters or detection limit and fatty acid triglycerides into fatty acid conversion factor list

No. Name fatty detection limit (mg/100 g) Fi conversion coefficient transform coefficients Fj 1 butyric acid (C4. 0) 0.5 0.8627 0.8742 2 acid (C6. 0) 0.5 0.8923 0.9016 3 caprylic (C8. 0) 0.5 0.9114 0.9192

4 Kwai acid (C10. 0) 0.5 0.9247 0.9314 5 undecanoic acid (C11. 0) 0.5 0.9300 0.9363 6 lauric acid (C12. 0) 0.5 0.9346 0.9405 7 thirteen carbonate (C13. 0) 0.5 0.9386 0.9442 8 myristic acid (C14. 0) 0.5 0.9421 0.9473 9 nutmeg oleic acid (C14. 1n5) 0.5 0.9417 0.9470 10 fifteen carbonic acid (C15. 0) 0.5 0.9453 0.9502 A 11 pentadecenoic acid (C15. 1n5) 0.5 0.9449 0.9499 12 palmitic acid (C16. 0) 0.5 0.9481 0.9529 13 palmitoleic acid (C16. 1n7) 0.5 0.9477 0.9525 14 heptadecanoic acid (C17. 0) 0.5 0.9507 0.9552 15 seventeen carbon-acid (C17. 1n7) 0.5 0.9503 0.9549

16 Stearic acid (C18. 0) 0.5 0.9530 0.9573

17 Elaidic acid (C18. 1n9t) 0.5 0.9527 0.9570

Table A.1 (CONTINUED)

No. Name fatty detection limit (mg/100 g) Fi conversion coefficient transform coefficients Fj 18 oleic acid (C18. 1n9c) 0.5 0.9527 0.9571 19 trans-linoleic acid (C18. 2n6t) 0.5 0.9524 0.9568 20 linoleic acid (C18. 2n6c) 0.5 0.9524 0.9568

21 Peanut acid (C20. 0) 0.5 0.9570 0.9609

22 gamma- linolenic acid (C18. 3n6) 0.5 0.9520 0.9559 A 23 eicosenoic acid (C20. 1) 0.5 0.9568 0.9608 24 alpha- linolenic acid (C18. 3n3) 0.5 0.9520 0.9560 25 twenty-one carbonic acid (C21. 0) 0.5 0.9588 0.9628 26 eicosadienoic acid (C20. 2) 0.5 0.9565 0.9605 27 behenic acid (C22. 0) 0.5 0.9604 0.9642

28 Eicosatrienoic acid (C20. 3n6) 0.5 0.9562 0.9598 29 erucic acid (C22. 1n9) 0.5 0.9602 0.9639

30 Eicosatrienoic acid (C20. 3n3) 0.5 0.9562 0.9598 31 arachidonic acid ARA (C20. 4n6) 0.5 0.9560 0.9597 32 twenty-three carbonic acid (C23. 0) 0.5 0.9620 0.9658 33 docosadienoic acid (C22. 2n6) 0.5 0.9600 0.9638 34 tetracosanoic acid (C24. 0) 0.5 0.9963 1.0002

35 Eicosapentaenoic acid EPA (C20. 5n3) 1.0 0.9557 0.9592

A 36 tetracosenoic acid (C24. 1n9) 1.0 0.9632 0.9666 Docosahexaenoic acid methyl ester DHA (C22. 6n3) 1.0 0.9590 0.9624

Note 1. Fi is converted into fatty acid methyl esters of fatty acids coefficient.

Note 2. Fj is converted into fatty acids, fatty acid triglyceride coefficients.

......
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