Thanks to Microfluidic Flow Control (MFC) technology you can generate precise HPLC gradients at nanoliter-per-minute flow rates, and maintain flow rate precision at levels that have not been previously attainable.
Microfluidic flow Control (MFC) technology is responsible for turning the theoretical benefits of nano- and micro-scale chromatography into distinct laboratory productivity advantages.
While nanoscale and capillary chromatography systems lacking MFC technology can demonstrate certain technical improvements over conventional HPLC systems under ideal conditions, they cannot duplicate the high degree of practical leverage that MFC-based systems contribute to laboratory productivity when put to the challenge of actual use.
The more you expect from your lab instrumentation, the more you'll appreciate the high flow rate precision, gradient formation accuracy, rapid response to flow rate change commands, data reproducibility and operational reliability of systems with MFC.
how MFC worksMFC systems have the following advantages:
By taking a novel approach to development, our direct-pumping Microfluidic Flow Control (MFC) technology eliminates the flow splitters found in traditional HPLC instrumentation, giving you the ability to adjust flow rates immediately for accurate, consistent, and precise nano LC/MS performance, run-after-run, and day-after-day.
Take advantage of the key benefits of MFC technology:Reproducible nanoscale gradients
NanoLC systems employ Eksigent's Microfluidic Flow Control (MFC) technology, which creates rapid, reproducible, low-flow-rate binary gradients by continuously measuring the temperature and the pressure differential across known flow resistances. Measurement of temperature allows the Nano LC systems to adjust for viscosity changes over extended run times and produces excellent retention time reproducibility day-to-day and month-to-month. Using MFC, NanoLC systems provide reproducible gradients at column flow rates of 20-100 nL/min without flow splitting. The system actively measures and controls flow rate in both mobile phases and is unaffected by column backpressure changes. This results in retention time reproducibility an order of magnitude greater than other HPLC systems.
No flow splitting
Rather than using positive displacement pistons or syringes to regulate flow, Eksigent systems rely on direct-pumping Microfluidic Control (MFC) technology. MFC uses continuous feedback to an electronically controlled pressure source to maintain precise nanoscale flow rates as low as 20 nL/min without flow splitting. By combining MFC with direct feedback of the flow rate, Eksigent NanoLC systems eliminate the flow inaccuracy and plumbing problems caused by flow splitting to provide precise flow rate control:
In addition, virtually instantaneous response to step changes in flow rate set point allow for ultra fast gradients and variable flow techniques like peak parking.
Automated peak parking
Give your mass spectrometer more time to identify more proteins. With the NanoLC, you can perform peak parking without the need for additional valves or external pumps and increase identification of co-eluting or low-abundance peptides. Peak parking using NanoLC dynamic flow control significantly extends MS/MS acquisition time while maintaining the resolution of downstream peaks. Reducing the flow rate allows for extended secondary analysis, increasing the number of unique peptides that can be identified per run.
In addition to precise control of gradients at nanoscale flow rates, MFC allows you to change the flow rate dynamically for higher speed sample loading or for extended MS/MS analysis (peak parking) to identify co-eluting and low abundance peptides. After the gradient, the system can automatically increase flow rate to accelerate flushing and reduce the lag time between sample runs. MFC flow control can be triggered by a signal from your mass spectrometer, eliminating the complexity of additional pumps or valves.
For example, the mass spectrometer may see multiple co-eluting peptides that require more than the typical peak width to allow MS/MS on all of them. The mass spectrometer can then send a signal to the Eksigent NanoLC system and the NanoLC system can lower the gradient rapidly, or peak park, to increase the mass spectrometer acquisition time. Because the mass spectrometer in nano electrospray is concentration sensitive rather than mass sensitive, this change in flow rate does not degrade sensitivity. After the peptides have been analyzed, the NanoLC system can resume the gradients normal flow rate, without loss of resolution in the downstream peaks.
Eksigent’s MFC capability allows the flow rate to be changed rapidly for higher speed sample loading or for extended MS/MS analysis (peak parking) to identify co-eluting and low abundance peptides. After the gradient, DFC can automatically increase the flow rate to accelerate flushing and reduce the lag time between sample runs. Dynamic Flow Control can be triggered with one mouse click or by a signal from the mass spectrometer, eliminating the complexity of previous approaches requiring additional pumps or valves.
Mixing at nanoliter/min flow rates
All flow control occurs upstream of the gradient mixer, the injection valve, and the LC column, so changes in backpressure as the analytical column ages or degrades are accounted for automatically, as are backpressure changes arising from changes in the mobile phase viscosity as the gradient proceeds.
High pressure gradient mixing at nanoliter/min flow rates does not require any additional volume beyond the 65 nl volume mixing tee. Within the capillary connecting the mixer with the injection valve, complete mixing will occur within the first 2.5 cm.
Read the MFC Tech Note.
