TLG® Ashless Quantitative Filter Papers No.40 are highly pure making them suitable for analyses sensitive to very low levels of background contamination. These filters are useful for gravimetric analysis, soil analysis for the separation of solid suspensions, preparation of solutions for Atomic Absorption Spectrometry (AAS), quantitative analysis of milk sediments, composition determinations, and collection of trace elements and radionuclides. SPECIFICATIONS Material: High Quality Cotton Linters Porosity: Medium Particle Retention in Liquid: 8µm Herzberg Filtration Speed: 335sec/100mL (or ASTM: 75sec) Nominal Thickness: 190 ± 10µm Nominal Weight: 90g/m² Nominal Ash Content : 0.007% Package Size: 100 Pieces