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This standard replaces GB 5009.265-2016 National food safety standard - Determination of polycyclic aromatic hydrocarbons in food.
The following main changes have been made with respect to GB 5009.265-2016:
——the original Method II - Gas chromatography-mass spectrometry is revised into Method I, where the determination items, sample preconditioning, gas chromatography-mass spectrometry conditions and calculation methods are modified;
——the original Method I - High-performance liquid chromatography is revised into Method II, where the serial numbers are modified, the principle is simplified, and the specimen preparation is unified.
National food safety standard -
Determination of polycyclic aromatic hydrocarbons in food
1 Scope
This standard specifies the determination method (Method I) for 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in food by gas chromatography-mass spectrometry and that (Method II) for 15 kinds of polycyclic aromatic hydrocarbons in food by liquid chromatography.
Method I in this standard is applicable to the determination of 16 kinds of polycyclic aromatic hydrocarbons (benzo[c]fluorene, benz[a]anthracene, cyclopenta[c,d]pyrene, chrysene, 5-methylchrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[j]fluoranthene, benzo[a]pyrene, indeno[1,2,3-c,d]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene) in grain/grain products, meat/meat products, aquatic animals/plants and aquatic products, animal and vegetable fats/oils and their products; it is also applicable to the determination of four kinds of polycyclic aromatic hydrocarbons (benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene) in formula milk powder and complementary foods for infants and young children.
Method II in this standard is applicable to the determination of 15 kinds of polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]fluoranthene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-c,d]pyrene, dibenz[a,h]anthracene and benzo[g,h,i]perylene) in grain/grain products, meat/products, aquatic animals/plants and aquatic products, and animal and vegetable fats/oils.
Method I Gas chromatography - mass spectrometry (GC-MS)
2 Principle
The polycyclic aromatic hydrocarbons in the specimens are extracted with solvents followed by saponification with potassium hydroxide solution in ethanol, and then purified with solid phase extraction columns. After concentration, the exacts are determined by gas chromatograph-mass spectrometer, and quantified by the isotope-labeled internal standard method.
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3 Reagents and materials
Unless otherwise specified, analytically-pure reagents and Class-I water specified in GB/T 6682 are used for the purpose of this method.
3.1 Reagents
3.1.1 Ethyl acetate (C4H8O2): chromatographically pure.
3.1.2 Dichloromethane (CH2Cl2): chromatographically pure.
3.1.3 Acetone (C3H6O): chromatographically pure.
3.1.4 Cyclohexane (C6H12): chromatographically pure.
3.1.5 N-heptane (C6H14): chromatographically pure.
3.1.6 Isooctane (C8H18): chromatographically pure.
3.1.7 Anhydrous ethanol (C2H6O): chromatographically pure.
3.1.8 Ammonium hydroxide (NH3·H2O): with a mass fraction of about 25%.
3.1.9 Ethyl ether absolute (C4H10O)
3.1.10 Petroleum ether (C5H12O2): with a boiling range of 30℃~60℃.
3.1.11 Potassium hydroxide (KOH).
3.1.12 Anhydrous sodium sulfate (Na2SO4): baked at 400℃ for 2h before use, and then put in a dryer for later use.
3.2 Preparation of reagents
3.2.1 Potassium hydroxide-ethanol solution (0.3mol/L): weigh out 1.68g of potassium hydroxide and dissolve it in 100mL of anhydrous ethanol by ultrasound. Freshly prepared.
3.2.2 Potassium hydroxide-ethanol solution (1.5mol/L): weigh out 8.40g of potassium hydroxide and dissolve it in 100mL of anhydrous ethanol by ultrasound. Freshly prepared.
3.2.3 Cyclohexane-ethyl acetate solution (1+1): mix cyclohexane and ethyl acetate uniformly at a ratio of 1:1 (volume ratio).
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3.2.4 Dichloromethane-ethyl acetate solution (1+1): mix dichloromethane and ethyl acetate uniformly at a ratio of 1:1 (volume ratio).
3.2.5 Acetone-isooctane solution (1+1): mix acetone and isooctane uniformly at a ratio of 1:1 (volume ratio).
3.3 Standard solution
3.3.1 Standard solution of polycyclic aromatic hydrocarbons
Standard solution of polycyclic aromatic hydrocarbons (containing benzo[c]fluorene, benz[a]anthracene, cyclopenta[c,d]pyrene, chrysene, 5-methylchrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[j]fluoranthene, benzo[a]pyrene, indeno[1,2,3-c,d]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene of 10.0μg/mL or corresponding concentrations): standard solution certified by the state and issued with the reference material certificate, stored at -18℃ away from light. See Annex A for CAS numbers of polycyclic aromatic hydrocarbons.
3.3.2 Internal standard solution of isotope-labeled polycyclic aromatic hydrocarbons
The internal standard solution of isotope-labeled polycyclic aromatic hydrocarbons (at least containing D12-benz[a]anthracene, D12-benzo[b]fluoranthene, D12-benzo[b]fluoranthene, D12-benzo[a]pyrene, D12-indeno[1,2,3-c,d]pyrene, D14-dibenz[a,h]anthracene, D12-benzo[g,h,i]perylene of 100.0μg/ml or corresponding concentrations), stored at -18℃ away from light. See Annex A for CAS numbers of the internal standard solution of isotope-labeled polycyclic aromatic hydrocarbons.
Caution: polycyclic aromatic hydrocarbons are known to be carcinogenic, teratogenic and mutagenic, and their carcinogenicity increases with the increasing of the number of benzene rings. Special attention shall be paid to safety protection during the preparation of standard solutions, and they shall be operated in a fume hood to minimize exposure.
3.4 Preparation of working standard solutions
3.4.1 Standard working solution of polycyclic aromatic hydrocarbons (500.0ng/mL): pipette 0.50mL of standard solution of polycyclic aromatic hydrocarbons (10.0μg/mL) into a 10mL volumetric flask, dilute it with the acetone-isooctane solution (1+1) to the scale, mix the resultant solution well and then transfer it to a brown glass storage bottle, storing it at 4℃ away from light; use it within the storage period of 3 months.
Foreword II
1 Scope
Method I Gas chromatography - mass spectrometry (GC-MS)
2 Principle
3 Reagents and materials
4 Apparatuses
5 Analytical steps
6 Calculation and expression of results
7 Quality assurance/quality control
8 Precision
9 Miscellaneous
Method II High-performance liquid chromatography
10 Principle
11 Reagents and materials
12 Apparatuses
13 Analytical steps
14 Calculation and expression of results
15 Precision
16 Miscellaneous
Annex A English names, abbreviations, relative molecular masses and CAS numbers of the polycyclic aromatic hydrocarbons and their isotope internal standards
Annex B Reference retention time and monitoring ions for polycyclic aromatic hydrocarbons and their corresponding internal standards in determination by GC-MS
Annex C Total ion flow chromatogram (internal standard method) for determination by GC-MS for standard solution of polycyclic aromatic hydrocarbons
Annex D Mass chromatograms for the ions of target polycyclic aromatic hydrocarbons and the characteristic ions of their isotope-D internal standards determined by SIM
Annex E Liquid chromatogram for the standard solution of polycyclic aromatic hydrocarbons
