Ahlstrom manufactures a series of extremely high purity, acid washed filter papers designed for use in analytical and gravimetric analysis. The quantitative grades are manufactured from top quality cotton linters using ultra-pure, reverse-osmosis water and are further treated with dilute acid to remove any remaining organic and inorganic impurities. All quantitative grades are manufactured in a strictly controlled environment that ensures high uniformity and high purity from filter to filter. Quantitative analysis Low ash content 0.007% (Acid-wash treated) High wet-strength Consistent performance Custom cut Bulk packaging Ashless Grades (Ash 0.007%) These standard ashless grades are high purity filter papers suitable for routine quantitative gravimetric techniques and in the preparation of samples for use in analysis involving instrumental techniques. Ahlstrom 74: 2.0µm – Medium Speed This grade has medium flow rate and good particle retention and is the most commonly used acidwashed filter. Ahlstrom 74 covers a wide range of general ashless filtration applications. It is used for gravimetric analysis of numerous components (e.g.: cements, copper, clay, bismuth, silicon, iron) found in heavy industries such as construction, mining or steel. Ahlstrom 74 is also used as a high purity filter for speedy filtering of trace elements such as silver chromate, lead sulfate, zinc and ammonium hydroxides. Ahlstrom 74 is also found in general soil analysis for separating solid from aqueous extracts.