The Difference Between Qualitative and Quantitative Filter Papers

Filter paper is a kind of paper which has good filtering quality. It is loose and has a strong liquid absorbing performance. Assay laboratory often uses filter paper as the filtration medium to separate the solid from the solution.

In the current market, the filter papers are mainly divided into qualitative filter paper, quantitative filter paper, and chromatography qualitative filter paper. The former two kinds are basically made of cellulose, and they are not suitable for other filter papers such as glass microfiber filter paper.

In common, the qualitative filter paper, such as Qualitative Chromatography Filter Paper Grade: BIO-5, Qualitative Filter Paper Biology Grade: BIO-6, is used for qualitative chemical analysis and relevant filtering separation. Specifically, solution filtration and qualitative tests of chloride and sulfate which do not need the calculated values.

On the other side, the quantitative filter paper, such as Quantitative Medium Flow Filter Paper Grade: BIO-40, Quantitative Ashless Filter Paper Grade: BIO-41, is used for filtration with precisely calculated values, such as determination of residual value and undissolved substance. Generally, after filtering with quantitative filter paper, the filter needs to be processed in the high-temperature furnace. Moreover, during the manufacturing process of quantitative filter paper, the paper pulp is processed with hydrochloric acid and hydrofluoric acid and washed by distilled water. So, most of the impurities in the paper fibers will be removed, and the residual ash remains very few after firing.

While at the very beginning, we can distinguish from the literal meaning between quantitative and qualitative.

Quantitative refers to fixed quantity, more about physical properties. Qualitative refers to fixed quality, more about chemical properties.

Most impurities were removed by hydrochloric acid, hydrofluoric acid, and distilled water during fabricating quantitative filter paper. So, the effect of filter paper quantity can be neglected. This characteristic benefits ashing weighing analysis experiment after filtration also called gravimetric analysis test and corresponding analytical test in quantitative chemical analysis.

Hawach has 3 kinds of quantitative filter paper according to its filtration speed, fast, medium and slow. 3 kinds according to impurity content, that is, ashless grade (Ash Content 0.007%), hardened low ash (Ash Content 0.015%), hardened ashless (Ash Content0.006%).

Qualitative filter paper usually was added in a small amount of chemical stabilizer to increase the bursting resistance, therefore be stronger and more durable during the test. But pay attention to Kay nitrogen test, cuz nitrogen in the stabilizer will has an effect on the result.

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