T/FQIA 006-2022 Determination of Methyl Bromide Residues in Tea by Headspace Gas Chromatography-Mass Spectrometry

Scope

Scope: Scope This document specifies the method for determining the residual methyl bromide in black tea, white tea, green tea, and oolong tea by headspace gas chromatography-mass spectrometry. This document is applicable to the determination of methyl bromide residues in black tea, white tea, green tea, and oolong tea. Other types of tea can be referenced for implementation. Main technical content: 1. Scope This document specifies the method for determining the residual methyl bromide in black tea, white tea, green tea, and oolong tea by headspace gas chromatography-mass spectrometry. This document is applicable to the determination of methyl bromide residues in black tea, white tea, green tea, and oolong tea. Other types of tea can be referenced for implementation. 2. Normative references The contents of the following documents are essential provisions of this document through normative references. Among them, the referenced documents with a date are only applicable to the version corresponding to that date; the latest version (including all amendment sheets) of the non-dated referenced documents is applicable to this document. GB/T 6682  Rules and Test Methods for Water Used in Analytical Laboratories GB/T 8303  Preparation of Crushed Samples of Tea and Determination of Their Dry Matter Content 3. Terms and definitions This document does not define any terms or definitions. 4. Principle The tea samples are immersed in a saturated solution of sodium chloride in a sealed headspace bottle, and the system is heated at a certain temperature for a certain time to achieve equilibrium in the distribution of methyl bromide between the gas and liquid phases. Then, the gas portion is introduced into the headspace gas chromatograph for separation and determination by mass spectrometry, with quantification using the external standard method of the standard curve. Main content Title Chapter Foreword II 1    Scope 2    Normative reference

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