Ashless Filter Paper for Critical Analysis in Filtration Processes

Ash content amount

The ash content of filter paper is determined by weighing the residue of combustion under air at 900°C. The minimum ash content is critical to the weight method and is a valid measure of general purity levels. The ash amount produced after ashing distinguishes the quantitative filter paper and the qualitative filter paper. Note that quantitative and qualitative filter paper only applies to cellulose filter paper and does not apply to other types of filter paper, such as glass microfiber filter paper.

In the manufacturing process, the quantitative filter paper 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 the residual ash after burning is minimal and has little effect on the analysis results. The quantitative filter paper is mainly used for weighing the ash after filtration for analytical tests, i.e. weight analysis tests and the corresponding analytical tests in quantitative chemical analysis.

Ashless quantitative filter paper

Ashless filter paper belongs to quantitative filter paper, with the ash content less than 0.1mg, which is negligible on the analytical balance. It is commonly used in analytical laboratories as a filter medium to separate solutions from solids. Quantitative filter papers are specifically designed for sample preparation for gravimetric and instrumental analysis. These three types of quantitative analytical filter papers are available to meet specific needs.

1. Ashless quantitative filter papers: HAWACH BIO 40-44 filter papers have an ash content of approximately 0.007% and one special filter paper has an ash content of approximately 0.01%. These high purity filter papers are widely used in the filtration process of critical analysis. Such as Quantitative Medium Flow Filter Paper Grade: BIO-40, Quantitative Ashless Filter Paper Grade: BIO-41, Quantitative Laboratory Filter Paper Grade: BIO-42, Quantitative Roll Filter Paper Grade: BIO-43, Quantitative Cellulose Filter Paper Grade: BIO-44.

2. Hardened low ash content: Ash content is about 0.015% – after strong acid treatment, some trace metal elements of the paper are removed and it has high wet strength and high chemical resistance. This type of filter paper is particularly suitable for funnel filtration because its hard and smooth surface makes it easy to collect sediment.

3. Hardened ash-free: Ash content is about 0.005% – acid treatment gives it high wet strength, high chemical resistance and very low ash content. The hard surface makes it widely applicable to critical filtration processes.

In HAWACH, there are different types of filter papers with different filtration speed. Welcome to contact HAWACH team for technical specification.