Specifications, Chemical Analysis of Quantitative Filter Paper
Besides quantitative cellulose filter papers, Hawach qualitative cellulose filter papers are considered as the general purpose filter papers in the modern lab. The quantitative cellulose filter papers are made of cellulose fiber and manufactured from high-quality cotton linters which are treated to maximize alpha cellulose.
As the most stable form of cellulose, alpha-cellulose is approved with the highest degree of polymerization. Hawach qualitative cellulose filter papers are made from a high percentage of alpha cellulose, showing a sign of high quality and consistency.
The different grades of Hawach qualitative filter paper are based on the properties, of the different kinds of thickness, weight, and particle retention. Unlike the ashless quantitative filter papers, which can be burned off for analytical applications according to their ashless grades, qualitative papers are more suited for general purposes and a big range of applications in and out of the laboratory.
Hawach Standard qualitative filter papers are graded from BIO 1-6, and Hawach wet-strengthened qualitative filter papers are graded BIO 113 and BIO 91 as well. Hawach standard qualitative filter papers requiring medium retention and flow rate, are the most popular filter papers for clarifying liquids in daily applications, such as qualitative analytical separation for lead sulfate, calcium carbonate, and calcium oxalate.
Quantitative filter papers are widely used for quantitative and gravimetric analysis in the lab. To make them ash-less and achieve high purity, a special production process with acid is required in production, washing with HF or HCl acids, and cleaning with demineralized water followed. The specific processes make the quantitative filter papers achieve two characteristics: high resistance to wet state and low ash content. Called ash-free filter paper as well, the quantitative filter papers can be divided into three formats, ashless, hardened low ash, and hardened ashless. With a 0.007% ash maximum for grades 40 to 44, ashless quantitative filter papers are ideals for a wide range of critical analytical filtration procedures.
Treated with a strong acid to remove trace metals and produce high wet strength and chemical resistance, hardened low ash quantitative filter papers have a 0.015% ash maximum. These filters are particularly used for vacuum filtration, as the tough smooth surface of the filter can recover precipitates easily. Its high wet strength and chemical resistance are similar to the acid-hardened ashless filter papers. And hardened ashless quantitative filter papers, with 0.006% ash maximum, are hardened by acid. The process gives high wet strength and chemical resistance with extremely low ash content.
Performance of Ashless Filter Paper
Quantitative filter paper is made of 100% high-quality cotton linters and refined by special papermaking technology and equipment. It is a kind of pure cotton with high purity, uniform organization, and acid-base treatment, with a certain filtering speed and certain strength. The main feature is that the ash content is very low, also known as ashless filter paper; it is suitable for the gravimetric method and the corresponding analysis test in quantitative chemical analysis.
Materials Difference of Ashless Filter Paper
The process of qualitative filter paper is a kind of filter paper needed to detect the composition of substances, which is mainly used in the laboratory. The traditional qualitative filter paper uses single wood pulp as the raw material, which leads to poor filtration performance and poor water resistance of the qualitative filter paper for a short period of filtration, and it is easy to lead to paper leakage. Hawach qualitative filter paper is mixed with long fiber and short fiber, which makes up for the deficiency caused by single fiber-making filter paper. Qualitative filter paper has good water resistance and wet strength, and its service life is higher than that of ordinary qualitative filter paper.
Specifications of Quantitative Filter Paper
The filter paper used for quantitative analysis in chemical analysis is divided into different specifications of the fast, medium, and slow speeds according to the different filtration speeds. In addition to the performance of qualitative filter paper, the paper is more pure and its ash content is lower (less than 0.01%). Has good wet strength and resistance to dilute acid. The raw materials and production methods used in production are the same as those of qualitative filter paper, but the quality requirements are higher. After being made into paper, it is soaked in a mixture of hydrofluoric acid and hydrochloric acid to further remove impurities and then washed and dried. The washing water should be ion-exchange pure water or distilled water.
Retention Ability of Ashless Filter Paper
Medium retention force and flow rate are most often used in daily filtration. Qualitative filter paper is made of high-quality high-grade cotton, using modern unique paper-making technology and advanced paper-making equipment. It is a pure cotton paper with high purity, uniform structure, certain filtration speed, and certain strength. The products are widely used in scientific research, industry, agriculture, medicine, health, and environmental protection departments. It is used for qualitative, and quantitative analysis, and qualitative and quantitative color layer analysis and testing.
