GB/T 8306-2013Tea -- Determination of total ash content (English PDF)

Foreword

This standard was drafted in accordance with GB/T 1.1-2009 given rules.

This standard replaces GB/T 8306-2002 "Determination of total ash tea." This standard compared with GB/T 8306-2002, the main technical change of the following.

--- Twice the difference between the measurement results, total ash per 100g sample should not exceed 0.2g, modified to repeat the same sample under conditions the absolute difference between the measurement results obtained shall not exceed 5% of the arithmetic mean.

This standard uses redrafted law revision using ISO 1575. 1987 "Tea Determination of total ash." This standard and ISO 1575. 1987 Phase Ratio, the main technical differences are as follows.

--- 5g sample quality measurement modify 2g, ashing process does not add vegetable oil;

--- Repeatability. the difference between the two measurement results, total ash per 100g sample should not exceed 0.2g, modified to duplicate the conditions hereinafter A sample assay results obtained absolute difference shall not exceed 5% of the arithmetic mean;

--- The International Standard amend Chapter 6 of this standard sample 6.1 sampling;

--- Remove the ISO 1573. 1980 Chapter 9 test reports.

This standard also made the following editorial changes.

--- Remove the ISO 1573. 1980 Foreword.

The standard proposed by China Federation of Supply and Marketing Cooperatives.

This standard by the National Standardization Technical Committee of tea (SAC/TC339) centralized.

This standard was drafted. China Federation of Supply and Marketing Cooperatives Hangzhou Tea Research Institute, the National Tea Quality Supervision and Inspection Center.

1 Scope

This standard specifies the determination of total ash tea equipment and appliances, procedures and results of the calculation method for the determination.

This standard applies to the determination of total ash tea.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version suitable for use herein Member. For undated references, the latest edition (including any amendments) applies to this document.

GB/T 8302 sampling Tea (GB/T 8302-2013, ISO 1839. 1980, NEQ) GB/T 8303 Tea grated dry matter content of the sample preparation and measurement (GB/T 8303-2013, ISO 1572. 1980, MOD)

3 Terms and Definitions

The following terms and definitions apply to this document.

Total ash

Under specified conditions, the tea after 525 °C ± 25 °C burning ashing residue obtained after.

Principle 4

The sample was 525 °C ± 25 °C heating burning, decomposition of organic matter to the constant.

5 Apparatus and appliances

5.1 Crucible. Platinum porcelain or other conditions will not be affected by the determination of the material. High type, capacity 30mL.

5.2 Electric hot plate.

5.3 high-temperature furnace. temperature can be 525 °C ± 25 °C.

5.4 dryer. containing more effective desiccant.

5.5 crucible tongs.

5.6 Analysis of balance. a sense of the amount of 0.001g.

6 Measuring step