Filter paper is a kind of good filtration performance, paper loose, the liquid has a strong absorption performance. The Analytical laboratory used filter paper as the filtration medium to separate the solution from the solid. At present, there are three kinds of filter paper in our country, which are quantitative analysis of filter papers and qualitative analysis. The two concepts of quantitative filter paper and qualitative filter paper are all cellulose filter paper, which is not suitable for other types of filter paper such as glass micro-fiber filter paper. Qualitative filter paper is used for qualitative chemical analysis and corresponding filtration separation.

Qualitative filter paper is generally used to filter the solution, do chloride, sulfate, etc. do not need to calculate the numerical value of the qualitative test, and the quantitative filter paper is used for precision calculation of the filtration, such as the determination of residue, insoluble, and so on, general quantitative filter paper filter, still need to enter the High-temperature furnace 1. Quantitative analysis of filter paper in the manufacturing process, pulp through hydrochloric acid and hydrofluoric acid treatment, and through distilled water washing, most of the impurities in the fiber removal, so after the burning of residual ash is very little, the analysis of the results almost no impact, suitable for precision quantitative analysis. At present, the domestic production of quantitative analysis of filter paper, divided into fast, medium speed, slow three categories, in the filter tray with white belt (fast), blue belt (medium speed), red belt (slow) for the classification of signs. The shape of the filter paper is circular and square, and the specifications of the circular-type sheet are d9cm, DLLCM, d12.5cm, d15cm and d18cm in diameter.

The square Quantitative filter paper has 60cmx60cm and 30cmx30cm. 2. Qualitative Analysis filter Paper Analysis filter paper general residual ash more, only for general qualitative and filtration precipitation or solution suspension, can not be used for quality analyses. Qualitative analysis of filter paper types and specifications and quantitative analysis of the basic paper is the same, express fast, medium speed and slow, but printed on the fast, medium-speed, slow-speed words.

However, in the box on the filter paper does not indicate the use of quantitative and qualitative analysis of filter filters precipitation should be noted:

① generally use natural filtration, the use of filter paper and the ability to intercept solid particles, liquid and solid separation;

② because the mechanical strength and toughness of the filter paper are smaller, as far as possible with the filtration method, if you must speed up the filtration speed, in order to prevent the filtration caused by filtering failure, in the air pump filtration, can be based on the size of suction in the funnel stack 2~3 layer of filter paper, in the use of vacuum suction, in the funnel first cushion a dense filter cloth, above put filter paper;

③ filter paper should not be filtered hot concentrated sulfuric acid or nitric acid solution; 3. Chromatography qualitative analysis of filter paper chromatography is mainly used as a bear in the papers chromatographic method, the qualitative separation of the objects to be measured qualitative and quantitative analysis of the filters are 1th and 3rd, each of which is divided into fast, medium speed and three kinds of slow speed. In addition: the difference between the use of the quantitative filter paper and the qualitative filter paper is: The qualitative filter is used for qualitative chemical analysis and the corresponding filtration separation, and the quantitative filter paper is used in the gravimetric analysis and the corresponding analysis test in quantitative chemical analysis. The function of the quantitative filter paper is mainly used for the gray weighing analysis after filtration, the ash weight of each filter paper is a fixed value, and the qualitative filter is used for the general filtration function. The difference between the quantitative filter paper and the qualitative filter is mainly the amount of ash produced after ashing. The qualitative filter paper does not exceed 0.13%, the quantitative filter paper does not exceed equal to 0.0009%. Ash-Free filter paper it is a quantitative filter, its ash is less than 0.1mg, this weight in the analysis of the balance can be negligible. Note that the two concepts of quantitative filter paper and qualitative filter paper are cellulose filter paper, which is not suitable for other types of filter paper such as glass micro-fiber filter paper.