GB 5009.246-2016 PDF English
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Determination of titanium dioxide in foods
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GB 5009.246-2016: PDF in English GB 5009.246-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard -
Determination of titanium dioxide in foods
ISSUED ON. AUGUST 31, 2016
IMPLEMENTED ON. MARCH 1, 2017
Issued by. National Health and Family Planning Commission
of the People’s Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 4
Method I – Inductively coupled plasma-atomic emission spectrometry (ICP-
AES) ... 4
2 Principle ... 4
3 Reagents and materials ... 4
4 Apparatus ... 5
5 Sample preparation ... 5
5 Analytical procedures ... 6
6 Expression of analytical results ... 7
7 Precision ... 8
8 Others ... 8
Method II – Diantipyryl methane colourimetry ... 8
9 Principle ... 8
10 Reagents and materials ... 8
11 Apparatus ... 9
12 Sample preparation ... 9
13 Analytical procedures ... 10
14 Expression of analytical results ... 11
15 Precision ... 12
16 Limit of detection and limit of quantitation ... 12
Annex A Reference operating conditions for microwave digestion and ICP-
AES instruments ... 13
National food safety standard -
Determination of titanium dioxide in foods
1 Scope
This Standard specifies the Inductively coupled plasma-atomic emission spectrometry
and diantipyryl methane colourimetry for the determination of titanium dioxide in foods.
This Standard applies to the determination of titanium dioxide in flours, jams, preserved
fruits, dehydrated potatoes, deep-fried nuts and seeds, candies (including gam base
candies), cocoa products, chocolates and chocolate products (including cocoa butter
replacer chocolates and products), and coatings of candies, products of candy and
chocolate, decorative candies, toppings, sweet juices, flavored syrups, mayonnaises,
salad dressings, solid beverages, jellies, puffed foods, beverage turbidity agents and
konjac gel products.
Method I – Inductively coupled plasma-atomic
emission spectrometry (ICP-AES)
2 Principle
After acid digestion of sample, use an inductively coupled plasma-atomic emission
spectrometer for analysis and use standard curve external standard method for
quantitation.
3 Reagents and materials
Unless specified otherwise, all reagents used are analytically pure and the water is
grade two water as 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 Preparation of reagents
3.2.1 Sulfuric acid solution (5 + 95). measure 50 mL of sulfuric acid; add slowly into
950 mL of water; mix up.
3.2.2 Mixed acid [perchloric acid + nitric acid (1 + 9)]. measure 100 mL of perchloric
acid; add slowly into 900 mL of nitric acid; mix up.
3.3 Standard substance
Titanium dioxide (TiO2). primary reagent or spectrographically pure.
3.4 Preparation of standard solutions
3.4.1 Titanium standard stock solution (1,000 μg/mL). weigh 0.167 g of titanium dioxide;
add 5 g of ammonium sulfate; add 10 mL of sulfuric acid; heat to dissolve; allow to cool;
transfer to a volumetric flask of 100 mL; dilute to scale; mix up. Or use a standard
solution which has passes the national certification and awarded the certificate of a
standard substance.
3.4.2 Titanium standard using solution (10.0 μg/mL). absorb 1.00 mL of titanium
standard stock solution to pour into a volumetric flask of 100 mL; use sulfuric acid
solution (5 + 95) to dilute to scale.
3.4.3 Titanium standard serial working solutions. absorb 0.000 mL, 0.500 mL, 2.00 mL,
5.00 mL, 10.0 mL and 20.0 mL of titanium standard using solution; pour respectively
into a volumetric flask of 100 mL; use sulfuric acid solution (5 + 95) to dilute to scale;
prepare the titanium serial standard working solutions of 0.000 μg/mL, 0.050 μg/mL,
0.200 μg/mL, 0.500 μg/mL, 1.00 μg/mL and 2.00 μg/mL.
4 Apparatus
4.1 Inductively coupled plasma-atomic emission spectrometer.
4.2 Microwave digestion system.
4.3 Analytical balance. sensitivity 0.1 mg.
5 Sample preparation
5.1 Solid and semisolid sample
10.2.1 Mixed solution [perchloric acid + nitric acid (1 + 9)]. measure 100 mL of
perchloric acid; slowly add into 900 mL of nitric acid; mix up.
10.2.2 Hydrochloric acid solution (1 + 1). measure 100 mL of hydrochloric acid; slowly
add into 100 mL of water; mix up.
10.2.3 Hydrochloric acid solution (1 + 23). measure 10 mL of hydrochloric acid; slowly
add into 230 mL of water; mix up.
10.2.4 Sulfuric acid solution (2 + 98). measure 20 mL of sulfuric acid; slowly add into
980 mL of water; mix up.
10.2.5 Ascorbic acid solution (2%). weigh 2 g of ascorbic acid; use water to dissolve
before diluting to 100 mL; prepare immediately prior to use.
10.2.6 Diantipyryl methane solution (5%). weigh 5 g of diantipyryl methane; use
hydrochloric acid solution (1 + 23) (10.2.3) to dissolve and dilute to 100 mL.
10.3 Standard substance
Titanium dioxide (TiO2). primary reagent or spectrographically pure.
10.4 Preparation of standard solutions
10.4.1 Titanium standard stock solution (1,000 μg/mL). weigh 0.167 g of titanium
dioxide; add 5 g of ammonium sulfate; add 10 mL of sulfuric acid; heat to dissolve;
allow to cool; transfer to a volumetric flask of 100 mL; dilute to scale; mix up. Or use a
standard solution which has passes the national certification and awarded the
certificate of a standard substance.
10.4.2 Titanium standard using solution (10 μg/mL). absorb 1.00 mL of titanium
standard stock solution (10.4.1) to pour into a volumetric flask of 100 mL; use sulfuric
acid (2 + 98) to dilute to scale.
11 Apparatus
11.1 Ultraviolet spectrophotometer.
11.2 Microwave digestion system.
11.3 Analytical balance. sensitivity 1 mg.
12 Sample preparation
12.1 Solid and semisolid sample
use water to dilute to scale; shake up; place aside for 40 min. The concentrations of
titanium in standard serial working solutions are 0.000 μg/mL, 0.100 μg/mL, 0.200
μg/mL, 0.500 μg/mL, 1.00 μg/mL and 2.00 μg/mL.
13.5 Plotting of standard curve
Use the standard blank solution after developing as the reference; use a cuvette of 1
cm; at the wavelength of 420 nm; use the ultraviolet spectrophotometer to determine
the absorbance of standard serial working solutions after developing. Plot the standard
curve using the concentrations of standard serial working solutions as the abscissa
and the corresponding absorbances as the ordinate.
13.6 Determination
Under the same experimental conditions as those for the determination of standard
solutions, determine the absorbances of sample solution and blank solution after
developing. Obtain the concentrations of sample solution and blank solution based on
the standard curve (13.5) and the absorbances of blank solution and sample solution.
14 Expression of analytical results
The content of titanium dioxide in sample is calculated in accordance with Equation
(2).
where.
X – the content of titanium dioxide in sample, in mg/kg;
c – the concentration of titanium in sample solution after developing which is obtained
from the standard curve, in μg/mL;
c0 – the concentration of titanium in blank solution after developing which is obtained
from the standard curve, in μg/mL;
V1 – the volume made up for the first time after sample digestion, in mL;
50 – the volume made up of sample solution after developing, in mL;
m – the mass of sample, in g;
V2 – the volume of sample solution transferred for developing, in mL;
1.668 1 – 1 g of titanium is equivalent to 1.668 1 g of titanium dioxide.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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