1 Scope
This standard specifies the method for determination of tin in foods by hydride-atomic fluorescence spectrometry and phenylfluorone colorimetry.
This standard is applicable to the determination of tin in canned solid foods, canned beverage, canned jam, canned infant formula and complementary foods.
Method I Hydride-atomic Fluorescence Spectrometry
2 Principle
After digestion, the sample generates hydride (SnH4) of tin under the action of sodium borohydride, and is brought into an atomizer by carrier gas for atomization; under the irradiation of hollow cathode lamp of tin, tin atom at ground state is excited to upper state; it emits fluorescence with characteristic wavelength after being deactivated to ground state with fluorescence intensity directly proportional to the tin content; then compare it with a series of standard solutions for quantitation.
3 Reagents and Materials
Note: unless otherwise stated, reagents used in this method are all analytical reagents, water is Grade II water specified in GB/T 6682.
3.1 Reagents
3.1.1 Sulfuric acid (H2SO4): guaranteed reagent.
3.1.2 Nitric acid (HNO3): guaranteed reagent.
3.1.3 Perchloric acid (HClO4): guaranteed reagent.
3.1.4 Thiourea (CH4N2S).
3.1.5 Ascorbic acid (C6H8O6).
3.1.6 Sodium borohydride (NaBH4).
3.1.7 Sodium hydroxide (NaOH).
3.2 Reagent preparation
3.2.1 Mixed solution (4+1) of nitric acid and perchloric acid: measure 400 mL nitric acid and 100 mL perchloric acid, and mix them uniformly.
Foreword i
1 Scope
2 Principle
3 Reagents and Materials
4 Instrument and Equipment
5 Analysis Procedure
6 Expression of Analysis Result
7 Precision
8 Others
9 Principle
10 Reagents and Materials
11 Instrument and Equipment
12 Analysis Procedure
13 Expression of Analysis Result
14 Precision
15 Others
