When delicate particles are subjected to shear forces resulting from stirring or rapid sample flow, particles may fragment before they are measured. In some cases, such as protein-based drug formulations, shear stresses can result in the formation and growth of aggregate particles. MFI systems are designed to minimize shear forces by using a gravity-assisted design ensuring large and dense particles enter the viewing zone without the need for high flow rates. When stirring is required to maintain particles in suspension, this is accomplished using gentle, adjustable and precise stirring.
Samples are introduced to MFI instruments from vessels mounted on the Inlet Port which is positioned directly above the Flow Cell. Any vessel with the appropriate geometry can be used. The Inlet Port is custom fabricated to accept 1ml and 5ml pipette tips. It can also accept 2ml, 10ml and 20ml syringe barrels. This open architecture provides complete sample introduction flexibility for a variety of application needs.
Samples can also be introduced using the Bot1 high-throughput autosampler. Designed for seamless integration with the MFI 5000 series, Bot1 dramatically reduces operator hands-on time while increasing sample throughput. The Bot1 automates virtually all aspects of MFI, including sample introduction, system flushing, focusing, and verification.
By reducing the volume of fluid in the sample introduction lines and flow-cell, flushing requirements to achieve clean baselines and minimum sample volumes are significantly less that those required by traditional technologies. Sample volumes can therefore be as low as 200 µL for the standard configuration. Even smaller volumes are possible by taking special precautions.
