Excellims specializes in pairing electrospray ionization sources with high performance ion mobility spectrometry. Traditional IMS utilized mainly thermal desorption to create ions, a process which was efficient but not very versatile. Thermal desorption involves heating a swab containing the sample to very high temperatures, at which point the sample vaporizes and is swept in the gas phase to a charged needle. While swab sampling is convenient, thermal desorption relies on the volatility of a sample. Many heavier compounds, such as proteins, were unable to be ionized by thermal desorption. Others, like sugars, break down at high temperatures.
The introduction of electrospray ionization allows for ion mobility analysis of a much wider range of samples. Electrospray ionization occurs in the liquid phase; a liquid sample is pumped through a thin needle, and a voltage at the needle's tip forces the liquid sample to aerosolize. Electrospray ionization is widely used for LC-MS, because it requires ionization of a sample in the liquid phase.
Excellims offers two electrospray options: the DirectsprayTM source and the continuous infusion electrospray source. The novel Directspray source allows for direct sample injection off of the tip of a common laboratory syringe needle. The user simply draws a sample up into the syringe and places it in a built-in syringe pump. Upon closing the cover on the pump, the Directspray automatically applies a voltage to the needle tip and begins pumping the sample through the syringe and into the ion mobility drift tube. This is the fastest and easiest method of sample introduction by Directspray; an entire sample can be run in under one minute. The setup also eliminates cross-contamination, and is compatible with both reusable and disposable syringes.
The infusion ESI source is meant for use with an autosampler, LC instrument, or flow cell setup. Rather than applying a voltage to a syringe needle, the infusion source contains a built-in electrospray needle connected to a capillary line. The sample flows continuously into the drift tube, which is perfect for reaction monitoring or for use during an LC run. The infusion source can pair with an autosampler so that many samples can be run without interruption.