GB 5009.181-2016 PDF EnglishUS$70.00 · In stock · Download in 9 seconds
GB 5009.181-2016: National food safety standard - Determination of malondialdehyde in food Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB 5009.181: Historical versions
Similar standardsGB 5009.181-2016: National food safety standard - Determination of malondialdehyde in food---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GB5009.181-2016GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA National Food Safety Standard - Determination of malondialdehyde in food Issued on: AUGUST 31, 2016 Implemented on: MARCH 01, 2017 Issued by. National Health and Family Planning Commission of the PRC Table of ContentsForeword ... 3 1 Scope ... 4 2 Principles ... 4 3 Reagents and materials ... 4 4 Instruments and equipment... 5 5 Analytical procedures ... 6 6 Analysis results expression ... 7 7 Precision ... 7 8 Principles ... 7 9 Reagents and materials ... 8 10 Instruments and equipment... 9 11 Analytical procedures ... 9 12 Analysis results expression ... 9 13 Precision ... 10 14 Other ... 10 Appendix A Chromatogram of malondialdehyde thiobarbituric acid derivative standard solution ... 11 National Food Safety Standard - Determination of malondialdehyde in food1 ScopeThis Standard specifies the method for determination of malondialdehyde in food. Method 1 of this Standard is applicable to the determination of malondialdehyde in food. Method 2 of this Standard is applicable to the determination of malondialdehyde in animal and vegetable fats and oils. Method 1 High performance liquid chromatography2 PrinciplesThe sample is first extracted with acid solution. Then the extract is reacted with thiobarbituric acid (TBA) to form a colored compound. USE high performance liquid chromatography-diode array detector to determine; and external standard method to quantify.3 Reagents and materialsUnless otherwise stated, the reagents used in this method are of analytically pure; the water is Grade I water specified in GB/T 6682. 3.1 Reagents 3.1.1 Methanol (CH3OH). chromatographically pure. 3.1.2 Trichloroacetic acid (C2HCl3O2). 3.1.3 Ethylene diamine tetraacetic acid (C10H14N2Na2O8 · 2H2O). 3.1.4 Thiobarbituric acid (TBA) (C4H4N2O2S). 3.2 Preparation of reagents 3.2.1 Ammonium acetate solution (0.01 mol/L). WEIGH 0.77 g of ammonium acetate; ADD water to dissolve and dilute to 1000 mL; and USE a 0.45 μm filter to filter. 3.2.2 Trichloroacetic acid mixture. accurately WEIGH 37.50 g (accurate to 0.01 g) of trichloroacetic acid (3.1.2) and 0.50 g (accurate to 0.01 g) of ethylene diamine tetraacetic acid (3.1.3); USE water to dissolve, dilute to 500 mL. 3.2.3 Aqueous solution of thiobarbituric acid (TBA). accurately WEIGH 0.288 g (accurate to 0.001 g) of thiobarbituric acid (3.1.4) dissolved in water and diluted to 100 mL (If not easy to dissolve, it can be heated by ultrasonic until completely dissolved. After cooling, DILUTE to volume of 100 mL), equivalent to 0.02 mol/L. 3.3 Standard 1,1,3,3-tetraethoxypropane (also known as malondialdehyde acetal, C11H24O4, CAS number. 122-31-6). Purity≥97%. 3.4 Preparation of standard solutions 3.4.1 Standard stock solution of malondialdehyde (100 μg/mL). Accurately TRANSFER 0.315 g (accurate to 0.001 g) of 1,1,3,3-tetraethoxypropane to a 1000 mL volumetric flask; after dissolving in water, DILUTE to 1000 mL; SET in a refrigerator at 4 °C for storage. It is valid for 3 months. 3.4.2 Standard use solution of malondialdehyde (1.00 μg/mL). accurately PIPETTE 1.0 mL of standard stock solution of malondialdehyde (3.4.1); USE trichloroacetic acid mixture (3.2.2) to dilute to 100 mL; SET in a refrigerator at 4 °C for storage. It is valid for 2 weeks. 3.4.3 Standard series solution of malondialdehyde. accurately PIPETTE 0.10 mL, 0.50 mL, 1.0 mL, 1.5 mL, 2.5 mL of standard use solution of malondialdehyde in 10 mL volumetric flasks; ADD trichloroacetic acid mixture (3.2.2) to dilute to volume. The concentration of the series of standard solutions is 0.01 μg/mL, 0.05 μg/mL, 0.10 μg/mL, 0.15 μg/mL, 0.25 μg/mL. Prepared when used.4 Instruments and equipment4.1 High performance liquid chromatography. equipped with a diode array detector. 4.2 Balance. The sensitivity is 0.0001 g, 0.01 g. 4.3 Thermostatic oscillator. 4.4 Thermostatic water bath. to the standard curve, the concentration of malondialdehyde in the solution to be tested is obtained. The liquid chromatogram of malondialdehyde standard is shown in Appendix A.6 Analysis results expressionThe content of malondialdehyde in the sample shall be calculated according to formula (1). Where. X - The content of malondialdehyde in the sample, in milligrams per kilogram (mg/kg); c - The concentration of malondialdehyde in the sample solution obtained from the standard series curve, in micrograms per milliliter (μg/mL); V - The constant volume of sample solution, in milliliters (mL); m - The mass of sample represented by the final sample solution, in grams (g); 1000 - Conversion factor. The calculation result is expressed as the arithmetic mean of the two independent determination results obtained under repeated conditions. The result retains two significant figures.7 PrecisionThe absolute difference between the two independent determination results, obtained under repeated conditions, shall not exceed 10% of the arithmetic mean. Method 2 Spectrophotometry8 PrinciplesAfter the malondialdehyde is extracted by trichloroacetic acid solution, it reacts with thiobarbituric acid (TBA) to form a pink compound. Its absorbance at 532 nm of wavelength is measured and compared with the standard series to to dilute to volume. The concentration of the series of standard solutions is 0.01 μg/mL, 0.05 μg/mL, 0.10 μg/mL, 0.15 μg/mL, 0.25 μg/mL. Prepared when used.10 Instruments and equipment10.1 Spectrophotometer. 10.2 Balance. The sensitivity is 0.0001 g, 0.01 g. 10.3 Thermostatic oscillator. 10.4 Thermostatic water bath.11 Analytical procedures11.1 Sample preparation WEIGH 5 g (accurate to 0.01 g) of the sample; PLACE it in a 100 mL conical flask with stopper; accurately ADD 50 mL of trichloroacetic acid mixture; SHAKE it well; and USE the stopper to seal. PLACE on a thermostatic oscillator to shake at 50 °C for 30 min; REMOVE, and COOL to room temperature. USE double-layer quantitative slow filter paper to filter; DISCARD the primary filtrate; and the subsequent filtrate is standby. Accurately PIPETTE 5 mL of the above filtrate and of standard series solution respectively; PLACE them in 25 mL colorimetric tube with stopper. TAKE another 5 mL of trichloroacetic acid mixture as a sample blank; ADD 5 mL of aqueous solution of thiobarbituric acid (TBA) respectively; COVER the stopper; and MIX well. PLACE in a 90 °C water bath to react for 30 min; TAKE out; and COOL to room temperature. 11.2 Determination USE the sample blank to adjust the zero point. At 1 cm optical path at a wavelength of 532 nm, the absorbance of the sample solution and the standard series solution (9.4.3) is determined. USE the mass concentration of the standard series solution as the abscissa. USE the absorbance value as the ordinate. The standard curve is drawn.12 Analysis results expressionThe content of malondialdehyde in the sample shall be calculated according to formula (2). ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. 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