Preparing standard extraction thimbles is the first step of quality control of extraction thimbles in laboratory analysis.
The first step is preparing standard extraction thimbles for the sampling experiments. You should pick ten extraction thimbles from those tested by the previous examinations, and number them from one to ten.
And then you should wet them slightly with deionized water and distilled water. Put the numbered extraction thimbles into the oven and dry them with a constant temperature between 105 ℃ and 110 ℃ for four hours.
After that, put them in the exclusive bottles for weighing, and put the bottles in the dryer. Cool them to room temperature and cover the exclusive bottles. Dry them repeatedly until the difference values of two adjacent weights do not exceed 0.0005g.
You should weigh the extraction thimbles 10 times according to the above methods and calculate the average value and relative standard deviation of each extraction thimble. The extraction thimbles with a relative standard deviation of less than 5% can be used as the standard extraction thimble.
The standard quality of standard extraction thimbles can be used for quality control in the process of drying, cooling, and weighing of sampling.
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