Electrospray Emitters
LOTUS emitters
Hydrophobic coating locks the meniscus to the inner diameter of the emitter
Better protein ID and reproducibility
The LOTUS emitters are built upon the optimized Sharp Singularity geometry
Classic Sharp Singularity emitters
Stable and repeatable signals require extremely tight tolerances at the microscopic scale. Our unique micro-machining process produces:
extremely sharp emitters
constant inner diameter (from 10 to 50 μm ID)
very tight tolerances.
Know everything about each emitter. Each and every emitter is inspected and photographed. You will get the a quality control and traceability report for every emitter.
Improve the quality of your data.
Start by selecting the right emitter for you in three steps:
1- Select the surface chemistry of your emitter (LOTUS or Classic):
LOTUS
The LOTUS emitters have a surface treatment that makes them hydrophobic. The liquid does not wet it, and the meniscus is anchored at the inner edge of the tip. For the same geometry, the lotus emitters produce smaller meniscus. This improves ionization efficiency and repeatability. As a weakness, the LOTUS surface treatment can be damaged over time due to the exposition to fluing ions (the tip of the electrospray is a very harsh environment!!). When testing the LOTUS, we recommend rising the voltage slowly to prevent the formation of a corona, that would rapidly erode the LOTUS treatment. The lotus is for you if you are interested in pushing the performance of your set-up to get the best data quality.
Classic:
All Sharp Singularity emitters are made of quartz silica. For optimum performance, the inner surface is rinsed with acidified water, but you will need to condition it for your set-up. This will happen automatically in the first two runs of your nLC workflow. When you install a new emitter, we recommend you to pas two standard runs before analyzing your samples.
The Classic surface finish is polished and rinsed with acidified water (HPLC grade). Under the influence of the electric field, the liquid wets the glass and the meniscus is anchored at the outer edge of the tip. The tipical voltages required to stabilize the classic emitters is 2.0KV to 2.5kV. The Classic is for you the conservatives.
Download brochure to learn more about the LOTUS effect:
2- Select the inner diameter of the emitter:
Selecting the right ID of the emitter is a trade-off decision between spray stability and robustness (smaller IDs provide better performance but are more susceptible to clogging)
For proteomics applications, the most commonly used emitters are 20μm and 10μm. (we can provide emitters from 10μm ID to 50μm ID).
The ideal emitter ID depends on the application and the flow rate:
for flow rates above 250nlpm, we recommend the 20μm ID;
for flow rates below 200nlpm, we recommend the 10μm ID;
for flows in between, we recommend testing both diameters and choosing whichever works best for your set-up and your application.
You can order a pack of of emitters with a mix of IDs to test.
20 um ID
10 um ID
3- Select the length of your emitters:
The Sharp Singularity emitters are straight cut and polished at the back to ensure they sit properly in their fitting. This eliminates imperfection at the back end of the emitter that can induce bubble nucleation, which is a main cause of spray instability. For this reason, we recommend not to cleave the emitters. If you ned a special length, please contact us and we will be happy to assist you to.
Improve the quality of your data, continue learning!:
The ionization efficiency depends on the size of the 1st generation nano-electrospray droplets, which is defined by the nano jet, which emerges from the electrospray meniscus, whose shape is determined by the emitter. To produce a stable signal, you need to produce a microscopic and stable meniscus. Having the right emitter is a good start. Understanding the physics of electrospray will help you get the best results. Here you can find some material to learn more:
Some reasons why reducing the size of the meniscus helps:
Solvent evaporation is desirable at the droplets but too much evaporation at the meniscus increases the concentration of contaminants reaching the jet. This enhances ion suppression effects and changes the properties of the liquid, affecting the droplet size, and the optimum the flow and voltage conditions. Smaller meniscus means less solvent evaporation.
Ion evaporation is desirable at the droplets but, at the vicinity of the nano-jet, this further ionize the gas because of high energy collisions induced by the strong electric fields. These gas ions reduce the droplets charge and hence their ionization efficiency. Ion evaporation is enhanced by solvent evaporation. Smaller meniscus means less ion evaporation.
Corona discharges form in the gas surrounding the meniscus when the voltage is too high. Ions formed at the discharge are attracted to the droplets and reduce their net charge. The voltage required to form an electrospray depends on the meniscus size. Small meniscus means low voltages an no corona discharges.
Ion transport: Smaller meniscus produce weaker electric fields pushing the ions forward. For this reason, nano-electrospray must be located very close to the MS inlet. The smaller the meniscus, the smaller the emitter to MS inlet distance.
CUSTOMER REVIEWS:
BC Cancer Research Centre (Canada) - Selfpack Dragonfly nano-Column with LOTUS emitter
“Overall, we are very happy with the performance of the LOTUS (Dragonfly) columns. They pack very easily and are extremely stable. This latter aspect is probably the best part about them, the tip performance never seems to degrade. Usually with self-pulled emitters, the tip performance will degrade after 100 injections or so in my experience. The first column I packed in the LOTUS emitter column lasted for over 1000 injections without a drop in performance (and this wasn't continuous usage either, it was uninstalled and reinstalled many times). The only reason I stopped using that one actually was it looked like the capillary around the column-emitter junction was starting to become a bit worn out and I was worried it was going to break, but the tip itself was still fine”.
Acoustica Bio (USA) - LOTUS emitters ref. 50-05 and 30-05.
“The emitters worked great! Congrats on your products – they are very well made.“
The Kennedy Group - University of Michigan (USA) - 20 μm ID with a flow rate of 250-750 nL/min.
"We use The Sharp Singularity nano-ESI emitters with our Q-Tof Premier Mass Spectrometer from Waters. They are working really well for us. The spray stability we can reach with them is better than with other brands we have tried in the past!"
Max-Planck-Institut für molekulare Zellbiologie u. Genetik (Germany) - 20 μm ID with a flow rate of 400-500 nL/min.
“We are very happy with "The Sharp Singularity" nano-ESI emitters. We work in proteomics, and we use them with all the Orbitraps in the lab. We have no bad words about them! They are very robust.”
Universitätsspital Zürich, USZ (Switzerland) - 20 μm ID
"Our group has been using FIT's products since many years ago, and we're very happy with them! The nano-ESI emitters The Sharp Singularity are working great with our Orbitraps. The first time we tried them we had some issues, but after a videocall with Guillermo (FIT's CTO) he gave us some tips and everything was solved"
Department of Infectious Diseases & Immunology - University of Florida (USA) - 20 μm ID with a flow rate of 180-300 nL/min.
"We have been using them with our Q-tof, and we are very happy with them. We had to get used to them because we were using pulled emitters before, but after using them for some time everything worked really well!"
Fondazione IRCCS - Istituto Nazionale dei Tumori (Italy) - 20 μm ID
"We are using the nano-ESI emitters The Sharp Singularity in our latest project and they are working very well. We use them 5 days a week, 5 hours per day, and the results are being very good! They seem cleaner than the New Objective ones we were using before"
National Research Council Canada (Canada) - 30 μm ID
"FIT's nano-ESI emitters are working very well for our experiments!"
Uniwersytet Gdański (Poland) - 10 μm ID with a flow rate of 300 nL/min.
“These nano-ESI emitters are working great for our research in peptidomics. We use them with our Orbitrap Exploris 480, and we are very satisfied with them.”
Integrity, cleanliness and handling:
The emitters are rinsed with HPLC grade solvents, and stored with low out-gassing materials to ensure they preserve their chemical properties.
Each emitter comes in an individual capillary guard to facilitate handling, storage, visual inspection, and quality control.
Some technical facts:
Why sharper is better:
The minimum wetting contact angle an emitter can accommodate is limited by its angle. Sharper emitters can accommodate wider wetting angles.
The electrostatic fields tangent to the surface of the emitter keeps the meniscus centered and aiming straight by compensating for the effect of the surface tension, which pushes the liquid to climb backwards. Sharper emitters produce more stable sprays because the tangent component of the electrostatic field is stronger. Sharper emitters can accommodate a wider range of local electric fields (voltages), surface tensions and wetting contact angles.
Choosing the right ID and tip-OD:
The size of the meniscus is defined by the OD at the tip. Smaller meniscus lead to lower evaporation rates, better ionization efficiencies, and better detection limits in proteomic workflows. They require lower voltages and delay the onset of discharges, leading to more stable sprays. On the other hand, small ID are more prone to clogging, and age more rapidly. The ideal emitter diameter is the result of a balance: The largest possible ID and the smallest possible tip OD. The choice of the ID of the emitters is a trade-off decision, between performance and robustness.
Pulling vs sharpening:
- Pulled capillaries form extremely small tip IDs, but they can be prone to clogging because the inner diameter decreases along the capillary length.
- Micro-machined capillaries can be more repeatable and robust because they can reach very tight geometric tolerances with a constant inner diameter, less prone to clogging. But achieving very sharp edges is more difficult because more material needs to be removed.
- FIT’s unique micro-machining process produces very sharp emitters (7.5º semi-angle) with tight geometric tolerances and a constant ID. Thus combining the advantages of pulled and normal tapered emitters.
Full Quality and Traceability by default
All emitters are delivered with a Quality and Traceability control report, with microscopy photos to ensure you have all details about your spray. Download Quality and Traceability Report examples
