How To Choose The Correct Qualitative And Quantitative Filter Paper
The difference between qualitative and quantitative filter paper is that filter paper is a kind of paper with good filtering performance. The paper is loose and has a strong absorption performance for liquid. Analytical laboratories often use filter paper as a filter medium to separate solutions from solids. At present, there are three types of filter paper produced in China: quantitative analysis filter paper, qualitative analysis filter paper, and chromatographic qualitative analysis filter paper.
The two concepts of quantitative filter paper and qualitative filter paper are unique to cellulose filter paper and are not applicable to other types of filter paper such as glass microfiber filter paper. Qualitative filter paper is generally used to filter solutions for qualitative tests that do not require numerical calculations such as chlorides and sulfates. Quantitative filter paper is used for the precise calculation of numerical values such as residues and insoluble. We need to enter the high-temperature furnace for processing.
Quantitative analysis filter paper during the manufacturing process, the pulp is treated with hydrochloric acid and hydrofluoric acid and washed with distilled water to remove most impurities in the paper fibers, so there is little residual ash after burning, and it has little effect on the analysis results. , Suitable for precise quantitative analysis.
At present, the quantitative analysis filter paper produced in China is divided into three types: fast, medium and slow. The filter paper is classified by the white belt (fast), blue belt (medium speed), and red belt (slow speed). There are two types of filter paper: round and square. The specifications of round fixed paper are d9cm, dllcm, d12.5cm, d15cm, and d18cm. Square quantitative filter paper is 60cm × 60cm and 30cm × 30cm.
Choose the right filter paper
Choosing the right filter paper can be determined by considering the following four factors.
Hardness: The filter paper will become wet during filtration. Some experimental procedures for long-term filtration should consider using the tougher filter paper after wet water.
Filtration efficiency: The density and size of the small holes in the filter paper affect its filtration efficiency. High-efficiency filter paper has fast filtering speed and high resolution.
Capacity: The solid particles accumulated during filtration may block the pores on the filter paper, so the denser the pores are, the higher the capacity is, and the more filters are allowed to filter.
Applicability: Some filter papers are made using special manufacturing steps, for example, in the test medicine used to determine the nitrogen content in the blood, nitrogen-free filter paper must be used.
Note that the filter paper cannot filter zinc chloride, otherwise the filter paper will be damaged by zinc chloride corrosion.
How to properly choose filter paper There are several main considerations in filter paper selection:
1. Effective area The effective area is large, that is, if the filter paper has a large area, the dust holding capacity will be large, the resistance will be small, and the service life will belong. Of course, the cost will increase accordingly.
2. Fiber diameter The smaller the fiber diameter, the better the interception effect, and the higher the filtration efficiency.
3. Binder content in the filter material The binder content is high, the paper’s tensile strength is high, the filtration efficiency is high, the hair loss phenomenon is less, the filter material has less dust accumulation, and the resistance is good, but the resistance is correspondingly increased