Ahlstrom Grade 121 is a very thick grade offers finer particle retention than Grade 111 with high wet strength and loading capacity. Grade 121 is recommended for the clarification of liquid suspensions loaded with fine particulates. Grade 121 is also used in membrane prefiltration and is also found in quantification of solids, and LSC (Liquid Scintillation Counting) techniques that require high loading capacity.

• Grade: 121
• Retention in µm:  1.0
• Filtration Speed Herzberg sec/100mls: 143
• Filtration Speed Rapidity mls/min: 48
• Loading Capacity: Very High
• Whatman Cross Reference: GF/B
• Size: 5cm x 30cm rectangles
  
  Standard glass microfiber filters contain no binders or other additives that may cause interference to sensitive enzymatic or other chemical reactions. The unique characteristics of glass microfiber filters make its use particularly advantageous to laboratory filtration by enabling fast filtration of large volumes and difficult solutions without premature clogging.
  
  Applications for Ahlstrom glass microfiber filters include environmental analysis for water, wastewater, testing of soils, air pollution and monitoring, research and process biochemistry, and gravimetric analysis involving ignition of samples. Ahlstrom glass microfiber filters are also found in the filtration of hot gases and liquids, and in pre-filtration.