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GB 5009.92-2016: National food safety standard - Determination of calcium in foods 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 5009.92: Historical versions
Similar standardsGB 5009.92-2016: National food safety standard - Determination of calcium in foods---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/GB5009.92-2016GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA National food safety standard - Determination of calcium in foods Issued on. DECEMBER 23, 2016 Implemented on. JUNE 23, 2017 Issued by. National Health and Family Planning Commission of the People’s Republic of China; China Food and Drug Administration. Table of ContentsForeword... 3 1 Scope... 4 2 Principle... 4 3 Reagents and materials... 4 4 Instruments and equipment... 5 5 Analysis procedure... 6 6 Expression of analysis results... 8 7 Precision... 9 8 Others... 9 9 Principle... 9 10 Reagents and materials... 9 11 Instruments and equipment... 10 12 Analysis procedure... 10 13 Expression of analysis results... 11 14 Precision... 12 15 Others... 12 Annex A Microwave digestion temperature rise program reference conditions... 13 Annex B Flame atomic absorption spectrometry reference conditions... 14ForewordThis Standard replaces the determination method for calcium in GB/T 5009.92-2003 “Determination of calcium in foods”, GB 5413.21-2010 “National food safety standard - Determination of calcium, iron, zinc, sodium, potassium, magnesium, copper and manganese in foods for infants and young children, milk and milk products”, GB/T 23375-2009 “Determination of copper, iron, zinc, calcium, magnesium and phosphorus content in vegetables and derived products”, GB/T 14609-2008 “Inspection of grain and oils - Determination of copper, iron, manganese, zinc, calcium, magnesium in cereals and derived products by atomic absorption and flame spectrophotometry”, GB/T 14610-2008 “Inspection of grain and oils - Determination of calcium in cereals and cereal products”, GB/T 9695.13-2009 “Meat and meat products - Method for Determination of calcium content” and NY 82.19-1988 “Determination of fruit juice - Determination of calcium and magnesium”. Compare this Standard with GB/T 5009.92-2003, the main changes are as follows. - MODIFY the standard name TO "National food safety standard - Determination of calcium in foods"; - ADD the microwave digestion, pressure tank digestion; - MODIFY the flame atomic absorption spectrometry and EDTA titration; - ADD the inductively coupled plasma emission spectrometry; - ADD the inductively coupled plasma mass spectrometry. National food safety standard - Determination of calcium in foods1 ScopeThis Standard specifies the determination of calcium in foods by flame atomic absorption spectrometry, titration, inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. This Standard applies to the determination of calcium content in foods. Method 1 -- Flame atomic absorption spectrometry2 PrincipleAfter the sample is digested, add lanthanum solution as the releasing agent, atomize by atomic absorption flame, and measure the absorbance value at 422.7 nm, which is proportional to the calcium content in a certain concentration range. Compare with the standard series.3 Reagents and materialsUnless otherwise specified, the reagents used in this method are excellent regents, and the water is Grade 2 water as specified in GB/T 6682. 3.1 Reagents 3.2 Preparation of reagents 3.2.1 Nitric acid solution (5 + 95). MEASURE 50 mL of nitric acid; ADD 950 mL of water; MIX well. 3.3 Standard Calcium carbonate (CaCO3, CAS No. 471-34-1). Purity > 99.99 %, or calcium standard solution at a certain concentration certified by the state and awarded the standard substance certificate. 3.4 Preparation of standard solutions 3.4.1 Calcium standard stock solution (1000 mg/L). accurately WEIGH 2.4963 g (to the nearest 0.0001 g) of calcium carbonate; ADD hydrochloric acid solution (1 + 1) to dissolve; TRANSFER to a 1000 mL volumetric flask; ADD water to the mark; MIX well.4 Instruments and equipmentNOTE. All glassware and polytetrafluoroethylene digestion inner tank must be soaked in nitric acid solution (1 + 5) overnight, washed repeatedly with tap water, and finally rinsed with water. 4.1 Atomic absorption spectrometer. with flame atomizer, calcium hollow cathode lamp. 4.4 Adjustable electric furnace. 4.5 Adjustable electric hot plate. 4.6 Pressure digestion tank. with polytetrafluoroethylene digestion inner tank. 4.7 Constant temperature oven.5 Analysis procedure5.1 Sample preparation NOTE. Sample contamination shall be avoided during sampling and sample preparation processes. 5.2 Sample digestion 5.2.1 Wet digestion Accurately WEIGH 0.2 g ~ 3 g (to the nearest 0.001 g) of solid sample or accurately PIPETTE 0.500 mL ~ 5.00 mL of liquid sample in a graduated digestion tube; 5.2.2 Microwave digestion Accurately WEIGH 0.2 g ~ 3 g (to the nearest 0.001 g) of solid sample or accurately PIPETTE 0.500 mL ~ 3.00 mL of liquid sample in a microwave digestion tank; ADD 5 mL of nitric acid. DIGEST the sample according to procedure of the microwave digestion, refer to Annex A for digestion conditions. REMOVE the digestion tank after cooling; PLACE it on the electric hot plate to get rid of acid to about 1 mL at 140 °C ~ 160 °C. After the digestion tank is cool, TRANSFER the digestion solution to a 25 mL volumetric flask; 5.3 Instrument reference conditions See Annex B for reference conditions. 5.4 Plotting of standard curve The calcium standard series solutions are introduced into the flame atomizer according to the order of the concentration from low to high, the absorbance values are measured. The standard curve is plotted by taking the concentration of calcium in the standard series solutions as the abscissa and the corresponding absorbance values as the ordinate.6 Expression of analysis resultsThe content of calcium in the sample is calculated according to equation (1).7 PrecisionThe absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10 % of the arithmetic mean.8 OthersWhen weighing 4 g (or 4 mL) of sample, diluting to the constant volume of 25 mL for calculation,9 PrincipleWithin the proper pH range, calcium forms metal complex with EDTA (disodium ethylenediaminetetraacetate).10 Reagents and materialsUnless otherwise specified, the reagents used in this method are analytical regents, and the water is Grade 3 water as specified in GB/T 6682. 10.1 Reagents 10.1.6 Calcium red indicator (C21O7N2SH14). 10.1.7 Nitric acid (HNO3). excellent regent. 10.1.8 Perchloric acid (HClO4). excellent regent. 10.2 Preparation of reagents 10.2.1 Potassium hydroxide solution (1.25 mol/L). WEIGH 70.13 g of potassium hydroxide; DILUTE with water to 1000 mL; MIX well. 10.2.6 Hydrochloric acid solution (1 + 1). MEASURE 500 mL of hydrochloric acid; MIX well with 500 mL of water. 10.3 Standard Calcium carbonate (CaCO3, CAS No. 471-34-1). with purity > 99.99 %, or calcium standard solution at a certain concentration certified by the state and awarded the standard substance certificate. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
