Filter Paper Classification
Qualitative filter paper refers to “qualitative analysis filter paper”, and qualitative analysis filter paper is relative to quantitative analysis filter paper. Filter paper is a kind of paper with good filtration performance. The paper is loose and has strong absorption properties to liquid. The filter paper commonly used in the analytical laboratory is used as a filter medium to separate the solution from the solid.
Hawach filter paper is mainly divided into two types: quantitative analysis filter paper and qualitative analysis filter paper.
1. Quantitative analysis of filter paper
Quantitative analysis of filter paper In the manufacturing process, the pulp is treated with hydrochloric acid and hydrofluoric acid, and washed with distilled water to remove most of the impurities in the paper fiber, so there is little residual ash after burning, and the analysis result is hardly It has an impact and is suitable for precise quantitative analysis.
Quantitative analysis of filter paper, divided into fast, medium and slow speeds. The specifications of the filter paper are divided into several types according to the diameters of 7cm, 9cm, 11cm, 12.5cm, 15cm and 18cm.
2. Qualitative analysis filter paper
Qualitative analysis filter paper generally has more residual ash, which is only for general qualitative analysis and for filtration precipitation or suspension in solution, and can not be used for quality analysis.
The type and specification of the qualitative analysis filter paper are basically the same as the quantitative analysis filter paper, indicating fast, medium speed and slow speed, but printed with fast, medium speed and slow speed. However, when using the quantitative and qualitative analysis filter paper to filter the sediment on the filter paper box, please pay attention to:
1. Generally use natural filtration, the use of filter paper and the ability to retain solid particles to separate the liquid and solid;
2. Due to the mechanical strength and toughness of the filter paper Filtering is as little as possible by suction filtration. If the filtration speed must be increased, the filtration failure is prevented to prevent the filtration. When the air pump is filtered, 2 to 3 layers of filter paper can be stacked in the funnel according to the pumping force. When pumping, it is leaking. First, a layer of dense filter cloth is placed on top, and then filter paper is placed on top;
3. Filter paper is best not to filter hot concentrated sulfuric acid or nitric acid solution.
The pore size of the qualitative filter paper is irregular, and the pores of the qualitative filter paper are usually large and quantitative. You can try using quantitative filter paper, the difference in filtration speed, and the difference in aperture. Generally, the qualitative filter paper has a large aperture and is not strictly regulated. Quantitative filter paper is divided into three types: fast, medium and slow. The pore diameters are about 80-120 microns, 30-50 microns, and 1-3 microns, respectively.
What is the difference between quantitative filter paper and qualitative filter paper?
The difference between quantitative filter paper and qualitative filter paper is mainly the amount of ash generated after ashing. The qualitative filter paper should not exceed 0.1%, and the quantitative filter paper should not exceed 0.007%. The difference between 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 quantitative chemical analysis in gravimetric analysis test and corresponding analytical test.