This standard supersedes Determination of Titanium Dioxide in Foods (GB/T 21912-2008).
Compared with GB/T 21912-2008, this standard has the following main changes:
- the standard name was revised as "National Food Safety Standard - Determination of Titanium Dioxide in Foods".
- the application scope of the standard was modified.
- contents about specimen preparation were added.
- the pretreatment mode of microwave digestion in Method II was deleted.
- Appendix A was modified.
National Food Safety Standard
Determination of Titanium Dioxide in Foods
食品安全国家标准
食品中二氧化钛的测定
1 Scope
This standard specifies the inductively coupled plasma - atomic emission spectrometry and diantipyryl methane colorimetric method for titanium dioxide in foods.
This standard is applicable to the determination of titanium dioxide in flour, jam, cool fruits, glycyrrhiza products, dehydrated potatoes, fried nuts and seeds, candy (including gum candy), cocoa products, chocolate and chocolate products (including chocolate with cocoa butter alternatives and its products), coating of candy and of candy & chocolate products, decorative candy, cresting, sweet juice, flavored syrup, mayonnaise, salad dressing, powdered beverages, jelly, puffed food, beverage turbidity agent and konjac gel products.
Method I Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES)
2 Principle
After being digested in acid, the specimen is analyzed with inductively coupled plasma atomic emission spectrometer and quantized by standard curve external standard method.
3 Reagents and Materials
Unless otherwise specified, the reagents adopted in this method are all analytically pure, and the water is Grade 2 water specified in GB/T 6682.
3.2.1 Sulfuric acid solution (5+95): measure 50mL of sulfuric acid, put it into 950mL of water slowly and mix them uniformly.
3.2.2 Mixed acid [perchloric acid + nitric acid (1+9)]: measure 100ml of perchloric acid, put it into 900mL of nitric acid slowly and mix them uniformly.
3.3 Standard substance
Titanium dioxide (TiO2): reference reagent or spectrally pure reagent.
3.4 Preparation of standard solution
3.4.1 Standard stock solution of titanium (1 000μg/mL): weigh 0.167g of titanium dioxide, add 5g of ammonium sulfate and 10mL of sulfuric acid, heat them until they are dissolved, then cool and transfer the solution to a 100mL volumetric flask, dilute to the scale and mix it uniformly. Or use the state-certified standard solution with reference material certificate.
3.4.2 Standard working solution of titanium (10.0μg/mL): pipet 1.00mL of standard stock solution of titanium and put it into a 100mL volumetric flask, then dilute with sulfuric acid solution (5+95) to the scale.
3.4.3 Standard series working solution of titanium: pipet 0.000mL, 0.500mL, 2.00mL, 5.00mL, 10.0mL and 20.0mL of standard working solution of titanium and put them into 100mL volumetric flasks respectively, dilute with sulfuric acid solution (5+95) to the scale to prepare into series of standard working solution of titanium with concentrations of 0.000μg/mL, 0.050 0μg/mL, 0.200μg/mL, 0.500μg/mL, 1.00μg/mL and 2.00μg/mL.
4.3 Analytical balance: with sensitivity of 0.1mg.
5 Specimen Preparation
5.1 Solid and semi-solid samples
Take representative edible part, subject it to homogenization with tissue blender, mix it uniformly and then put it into clean container, seal and mark well.
5.2 Liquid sample
Take representative sample, mix it uniformly and then put it into clean container, seal and mark well.
Note: In the process of specimen preparation and preservation, the sample shall be prevented from pollution and to-be-determined substance shall be prevented from loss.
6 Analytical Procedures
6.1 Specimen processing
6.1.1 Ordinary wet digestion
Weigh about 5g (to the nearest of 0.001g) of specimen, put it into a conical flask or tall beaker, then put into several glass beads and 15mL~20mL of mixed acid, cover the beaker with watch glass and put it on electric furnace for slowly digestion until the solution becomes clarified; if black after carbonization appears in the process of digestion, dropwise add nitric acid carefully under the condition of covering with watch glass until the solution is clarified. Keep heating until there is about 2mL~3mL of solution, cool it and add 1g of ammonium sulfate and 5mL of sulfuric acid, boil them until the solution becomes clarified; then keep boiling until white smoke of perchloric acid is totally driven out, take down the beaker and cool it, then transfer the solution to a 100mL volumetric flask, dilute it with water to the scale and mix uniformly for standby application.
6.1.2 Microwave digestion
Weigh 0.2g~0.5g (to the nearest of 0.000 1g) of specimen, put it into microwave digestion tank, add 2.5mL of nitric acid and 2.5mL of sulfuric acid, set appropriate microwave digestion condition for digestion; after the digestion, cool the digestion tank naturally to room temperature, transfer the digestion solution into a 50mL volumetric flask, wash the digestion tank with a small amount of water for many times, combine the washing liquid into volumetric flask, dilute with water to the scale and mix it uniformly. The digestion solution shall be clear solution; if there is sediment that cannot be digested, treat it with ordinary wet digestion again.
Note: Appendix A can be taken as a reference for temperature controlled microwave digestion working condition.
6.2 Blank test
Blank test is carried out according to 6.1.1 or 6.1.2 except for adding specimen.
6.3 Plotting of standard curve
Adjust inductively coupled plasma atomic emission spectrometer to the optimum condition to determine the emitted light strength of standard series working solution of titanium (3.4.3). Plot the standard curve by taking the concentration of titanium as horizontal coordinate and emitted light strength as longitudinal coordinate.
Note: Appendix A can be taken as a reference for the working condition of inductively coupled plasma atomic emission spectrometer.
6.4 Determination
Determine the emitted light strength of specimen solution and blank solution under the same experimental conditions with the determination of standard solution. Calculate the concentration of titanium in specimen solution and blank solution according to standard curve (6.3) and the emitted light strength of specimen solution. If the concentration of titanium in specimen solution is over high, dilute the solution properly.
Foreword i 1 Scope 2 Principle 3 Reagents and Materials 4 Instruments and Apparatus 5 Specimen Preparation 6 Analytical Procedures 7 Expression of Analysis Results 8 Precision 9 Others 10 Principle 11 Reagents and Materials 12 Instruments and Apparatus 13 Specimen Preparation 14 Analytical Procedures 15 Expression of Analysis Results 16 Precision 17 Limit of Detection and Limit of Quantitation Appendix A Reference Working Conditions for Microwave Digestion and ICP-AES Apparatus
This standard supersedes Determination of Titanium Dioxide in Foods (GB/T 21912-2008).
Compared with GB/T 21912-2008, this standard has the following main changes:
- the standard name was revised as "National Food Safety Standard - Determination of Titanium Dioxide in Foods".
- the application scope of the standard was modified.
- contents about specimen preparation were added.
- the pretreatment mode of microwave digestion in Method II was deleted.
- Appendix A was modified.
National Food Safety Standard
Determination of Titanium Dioxide in Foods
食品安全国家标准
食品中二氧化钛的测定
1 Scope
This standard specifies the inductively coupled plasma - atomic emission spectrometry and diantipyryl methane colorimetric method for titanium dioxide in foods.
This standard is applicable to the determination of titanium dioxide in flour, jam, cool fruits, glycyrrhiza products, dehydrated potatoes, fried nuts and seeds, candy (including gum candy), cocoa products, chocolate and chocolate products (including chocolate with cocoa butter alternatives and its products), coating of candy and of candy & chocolate products, decorative candy, cresting, sweet juice, flavored syrup, mayonnaise, salad dressing, powdered beverages, jelly, puffed food, beverage turbidity agent and konjac gel products.
Method I Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES)
2 Principle
After being digested in acid, the specimen is analyzed with inductively coupled plasma atomic emission spectrometer and quantized by standard curve external standard method.
3 Reagents and Materials
Unless otherwise specified, the reagents adopted in this method are all analytically pure, and the water is Grade 2 water specified in GB/T 6682.
3.1 Reagents
3.1.1 Perchloric acid (HClO4): guaranteed reagent.
3.1.2 Sulfuric acid (H2SO4): guaranteed reagent.
3.1.3 Nitric acid (HNO3): guaranteed reagent
3.1.4 Ammonium sulfate [(NH4)2SO4].
3.2 Reagent preparation
3.2.1 Sulfuric acid solution (5+95): measure 50mL of sulfuric acid, put it into 950mL of water slowly and mix them uniformly.
3.2.2 Mixed acid [perchloric acid + nitric acid (1+9)]: measure 100ml of perchloric acid, put it into 900mL of nitric acid slowly and mix them uniformly.
3.3 Standard substance
Titanium dioxide (TiO2): reference reagent or spectrally pure reagent.
3.4 Preparation of standard solution
3.4.1 Standard stock solution of titanium (1 000μg/mL): weigh 0.167g of titanium dioxide, add 5g of ammonium sulfate and 10mL of sulfuric acid, heat them until they are dissolved, then cool and transfer the solution to a 100mL volumetric flask, dilute to the scale and mix it uniformly. Or use the state-certified standard solution with reference material certificate.
3.4.2 Standard working solution of titanium (10.0μg/mL): pipet 1.00mL of standard stock solution of titanium and put it into a 100mL volumetric flask, then dilute with sulfuric acid solution (5+95) to the scale.
3.4.3 Standard series working solution of titanium: pipet 0.000mL, 0.500mL, 2.00mL, 5.00mL, 10.0mL and 20.0mL of standard working solution of titanium and put them into 100mL volumetric flasks respectively, dilute with sulfuric acid solution (5+95) to the scale to prepare into series of standard working solution of titanium with concentrations of 0.000μg/mL, 0.050 0μg/mL, 0.200μg/mL, 0.500μg/mL, 1.00μg/mL and 2.00μg/mL.
4 Instruments and Apparatus
4.1 Inductively coupled plasma atomic emission spectrometer.
4.2 Microwave digestion instrument.
4.3 Analytical balance: with sensitivity of 0.1mg.
5 Specimen Preparation
5.1 Solid and semi-solid samples
Take representative edible part, subject it to homogenization with tissue blender, mix it uniformly and then put it into clean container, seal and mark well.
5.2 Liquid sample
Take representative sample, mix it uniformly and then put it into clean container, seal and mark well.
Note: In the process of specimen preparation and preservation, the sample shall be prevented from pollution and to-be-determined substance shall be prevented from loss.
6 Analytical Procedures
6.1 Specimen processing
6.1.1 Ordinary wet digestion
Weigh about 5g (to the nearest of 0.001g) of specimen, put it into a conical flask or tall beaker, then put into several glass beads and 15mL~20mL of mixed acid, cover the beaker with watch glass and put it on electric furnace for slowly digestion until the solution becomes clarified; if black after carbonization appears in the process of digestion, dropwise add nitric acid carefully under the condition of covering with watch glass until the solution is clarified. Keep heating until there is about 2mL~3mL of solution, cool it and add 1g of ammonium sulfate and 5mL of sulfuric acid, boil them until the solution becomes clarified; then keep boiling until white smoke of perchloric acid is totally driven out, take down the beaker and cool it, then transfer the solution to a 100mL volumetric flask, dilute it with water to the scale and mix uniformly for standby application.
6.1.2 Microwave digestion
Weigh 0.2g~0.5g (to the nearest of 0.000 1g) of specimen, put it into microwave digestion tank, add 2.5mL of nitric acid and 2.5mL of sulfuric acid, set appropriate microwave digestion condition for digestion; after the digestion, cool the digestion tank naturally to room temperature, transfer the digestion solution into a 50mL volumetric flask, wash the digestion tank with a small amount of water for many times, combine the washing liquid into volumetric flask, dilute with water to the scale and mix it uniformly. The digestion solution shall be clear solution; if there is sediment that cannot be digested, treat it with ordinary wet digestion again.
Note: Appendix A can be taken as a reference for temperature controlled microwave digestion working condition.
6.2 Blank test
Blank test is carried out according to 6.1.1 or 6.1.2 except for adding specimen.
6.3 Plotting of standard curve
Adjust inductively coupled plasma atomic emission spectrometer to the optimum condition to determine the emitted light strength of standard series working solution of titanium (3.4.3). Plot the standard curve by taking the concentration of titanium as horizontal coordinate and emitted light strength as longitudinal coordinate.
Note: Appendix A can be taken as a reference for the working condition of inductively coupled plasma atomic emission spectrometer.
6.4 Determination
Determine the emitted light strength of specimen solution and blank solution under the same experimental conditions with the determination of standard solution. Calculate the concentration of titanium in specimen solution and blank solution according to standard curve (6.3) and the emitted light strength of specimen solution. If the concentration of titanium in specimen solution is over high, dilute the solution properly.
Contents of GB 5009.246-2016
Foreword i
1 Scope
2 Principle
3 Reagents and Materials
4 Instruments and Apparatus
5 Specimen Preparation
6 Analytical Procedures
7 Expression of Analysis Results
8 Precision
9 Others
10 Principle
11 Reagents and Materials
12 Instruments and Apparatus
13 Specimen Preparation
14 Analytical Procedures
15 Expression of Analysis Results
16 Precision
17 Limit of Detection and Limit of Quantitation
Appendix A Reference Working Conditions for Microwave Digestion and ICP-AES Apparatus
