Analytical Filter Papers

Ahlstrom's qualitative grades of filter paper are, by definition, recommended for use in analytical methods which determine or identify particulate constituents of a mixture irrespective of the amount present.

Grades in the 200 or 600 Series are suitable for quadrant folded or gravity flow applications. These grades contain a high level of alpha cellulose that provides high purity but will weaken when wet.

Applications using filter paper in a system under pressure or vacuum require the use of a high wet strength grade such as those in Ahlstrom's 900 Series. These grades contain a small amount of chemically stable, insoluble binding resin that strengthens the natural fiber to fiber bonds under wet conditions. Grades containing wood fiber or resins are not recommended for use in quantitative ashing techniques.

Quantitative (Ashless)

Ahlstrom Technical Specialties manufactures a line of extremely high purity, acid washed paper designed for use in analytical applications and gravimetric analyses. We manufacture these quantitative grades from 100% high quality cotton fibers using ultra-pure, reverse osmosis, water. A final acid treatment removes any remaining organic or inorganic impurities. All quantitative grades have a maximum ash content of 0.012%.

Specially treated, hardened ashless papers are available for applications requiring increased wet strength and handling capacity. These hardened grades have a tough, smooth surface free of loose fibers are ideal for collecting wet precipitates.

Pleated (Fluted) Grades

Ahlstrom's prepleated grades can save valuable time and maximize the efficiency of your filter system. Pleating increases the effective surface area increasing flow rate and loading capacity thus decreasing filtration time. We offer a full range of pleated filters to meet your needs from grades with rapid flow rates for filtration of viscous materials to grades with tight matrices for removal of fine precipitates. Pleated circles are available in 12.5 cm to 90 cm diameters.

Ahlstrom Paper Group, 122 West Butler Street, P.O. Box A, Mt. Holly Springs, PA 17065-0238. Tel: 717-486-5982; Fax: 717-486-6413.