The difference between quantitative filter paper and qualitative filter paper
The main difference between quantitative filter paper and qualitative filter paper lies in the amount of ash produced after ashing. Qualitative filter paper shall not exceed 0.13%, and quantitative filter paper shall not exceed or equal to 0.0009%. Note that both the concepts of quantitative filter paper and qualitative filter paper are unique to cellulose filter paper,
Not suitable for other types of filter paper such as glass microfiber filter paper.
The difference between the use of quantitative filter paper and qualitative filter paper is that qualitative filter paper is used for qualitative chemical analysis and corresponding filtration separation; Quantitative filter paper is used for qualitative chemical analysis and corresponding filtration separation; Quantitative filter paper is used for gravimetric analysis experiments and corresponding analytical experiments in quantitative chemical analysis.
Filter paper is a type of paper with good filtration performance. The paper is loose and has strong absorption properties for liquids. Filter paper is commonly used as a filtering medium in analytical laboratories to separate solutions from solids. At present, the filter paper produced in China mainly includes three types: quantitative analysis filter paper, qualitative analysis filter paper, and chromatographic qualitative analysis filter paper.
1. Quantitative analysis of filter paper
In the manufacturing process of quantitative analysis filter paper, the pulp is treated with hydrochloric acid and hydrofluoric acid, and then washed with distilled water to remove most of the impurities in the paper fibers. Therefore, the residual ash after burning is very small, which has almost no impact on the analysis results and is suitable for precise quantitative analysis.
At present, the quantitative analysis filter paper produced in China is divided into three categories: fast, medium, and slow. The filter paper boxes are classified with white ribbon (fast), blue ribbon (medium), and red ribbon (slow) as symbols. There are two types of filter paper in terms of shape: circular and square. Circular paper can be classified into several sizes based on diameter, including d9cm, dllcm, d12.5cm, d15cm, and d18cm. The square quantitative filter paper has a length of 60cm × 60cm and 30cm × 30cm.
2. Qualitative analysis of filter paper
Qualitative analysis filter paper generally contains a large amount of residual ash, which is only used for general qualitative analysis and for filtration precipitation or suspension in solutions, and cannot be used for quality analysis. The types and specifications of qualitative analysis filter paper are basically the same as those of quantitative analysis filter paper, indicating fast, medium, and slow speed, but printed with the words fast, medium, and slow. However, when using filter paper to filter sediment, it should be noted that: ① natural filtration is generally used, which utilizes the filter paper body and the ability to intercept solid particles to separate liquids and solids; ② Due to the mechanical strength and toughness of the filter paper, it is recommended to use less suction filtration to filter. If the filtration speed must be accelerated, in order to prevent filtration failure caused by filtration, 2-3 layers of filter paper can be stacked in the funnel according to the suction force during air pump filtration. When using vacuum filtration, a dense filter cloth should be placed on top of the filter paper before filtration It is best not to filter hot concentrated sulfuric acid or nitric acid solutions with filter paper.
