GB/T  8142-2008

Methods for sampling shellac products

1. Scope
This standard specifies the sampling method, sample preparation and sample preservation of shellac products.
This standard applies to granular shellac, shellac, decolorized shellac, dewaxed shellac, decolorized and dewaxed shellac, military shellac, bleached shellac and refined bleached shellac products.

2. Sampling method
2.1 number of samples collected

The sample for analysis should be sufficiently representative of the entire batch. The samples for inspection shall be selected from not less than 10% boxes (bags), at least 5 boxes and not more than 25 boxes at most from each batch of products, and shall be taken from different parts of the boxes (bags) that have not been opened in the original amount.
Sampling of 2.2 Loose Shellac Products
For the sampling of general loose shellac products, a sampling spoon can be used to extract approximately the same number of samples from different parts of each box (bag), with a total weight of about 5kg.
Sampling of 2.3 caked shellac products
For caked shellac products, samples are split or chiseled from different parts, and the amount of samples taken from each box (bag) is approximately equal, with a total weight of about 5kg.

3. Sample preparation
3.1 laboratory samples

Fully mix the extracted samples, divide them by quartering, subtract two pairs of diagonal samples and fully mix them. After dividing into four equal parts, mix two pairs of the sample, grind to completely pass through a sieve with an aperture of about 2mm (equivalent to 10 mesh) and mix thoroughly, and divide into four equal parts, each is about 300g. 3.2 analysis sample
3.2.1 Take 100g of the laboratory sample (3.1), crush it until it completely passes through a sieve with an aperture of about 0.4mm (equivalent to 40 mesh), and put it into a clean, dry, polished glass smooth mouth bottle for analysis and inspection. Stick a label on the bottle and indicate the name of the manufacturer, product name, batch number, sampling date and location, etc.
3.2.2 Take about 40g of laboratory sample (3.1), crush it until it completely passes through a sieve with an aperture of about 0.3mm (equivalent to 60 mesh), and put it into a clean, dry glass smooth mouth bottle with grinding mouth for analysis and inspection. Stick a label on the bottle and indicate the name of the manufacturer, product name, batch number, sampling date and location, etc.
3.2.3 Take about 10g of laboratory sample (3.1), crush it until it completely passes through a sieve with an aperture of about 0.2mm (equivalent to 80 mesh), and put it into a clean, dry glass smooth mouth bottle with grinding mouth for analysis and inspection. Stick a label on the bottle and indicate the name of the manufacturer, product name, batch number, sampling date and location, etc.

4. Sample preservation
The remaining 150g test sample (3.1) shall be put into a clean and dry wide-mouth bottle, sealed, and the bottle shall be labeled with the same content as 3.2.1, and shall be stored for later use.