Brief Introduction of Quantitative Filter Papers
(Ashless – ash content 0.007%)
The ash-free quantitative filter paper is a very pure filter paper, which is the ideal paper for most of the analysis of the filtration process.
Grade 40 is an ashless filter paper with conventional filtration, medium velocity and particle retention. Used for the analysis of specific gravity of cement, soil and metal. Used as a primary filter paper for solids separation from aqueous extracts in soil analysis, used in quantitative milk component analysis, and used as a pure analytical grade for clean filtration prior to atomic absorption spectroscopy. It is also used for the high-purity collection of residual elements and radionuclides in the atmosphere, or for collecting acid gases and alkaline gases in the atmosphere as impregnated filter paper, testing of total arsenic in food and feed, nitrate in forage, oxalic acid in canned vegetables, Fertilizer, such as boron content.
Grade 41 is the fastest flow rate ashless filter paper, which is recommended for analysis such as aluminum hydroxide or ferric hydroxide. It is also used for filtering large particles or gelatinous sediments, such as iron content in iron ore and filtration when magnesium content in magnesium ore is measured. It is also often used for the determination of ambient air pollutants such as suspended particulates, gaseous compounds such as fluoride ), Or filter digestion solution to do spectral, chromatographic or mass spectrometric analysis, such as picric acid turbidity, pectin acid determination in food, Grade 41 filter paper is also standard tear test strip matrix.
Grade 42 is the finest particle retention in all cellulose filters and is the world standard for gravimetric analysis.It is commonly used in the determination of elements such as barium sulfate, stannic acid, calcium carbonate, strontium carbonate and other minerals, filtering gasoline or organic solvents, and filtering preparation of spectrum and chromatographic samples, such as atomic absorption spectrometry (AAS), determination of two lauric acid two butyltin in feed.
The retention of Grade 43 filter paper particles is between Grade 40 and 41, but is twice as fast as that of Grade40. Typical applications include food analysis, soil analysis, and fluorescence analysis after particle collection of air pollution monitoring, and also for inorganic analysis in construction industry, mineral and steel industry.
Grade 44 is a thin version of Grade 42, which retention smaller particles, but the ash of each sample is lower, and the flow rate is almost two times that of Grade 42.