Can Emilie measure particle size?+
No. The infrared spectra recorded by EMILIE are independent of particle size. The size of the nanoparticles present in your sample can be evaluated with the help of commercially available methods. The choice of method will depend on your sample.
Do I need to scan the surface of the Emilie nanomechanical sampling and sensing chip?+
No. NEMS-IR is a bulk characterization method. The entire surface of the EMILIE sampling and sensing nanomechanical chip is illuminated at once by the light source during a measurement.
If my sample is a mixture, will the resulting spectrum show the overlapping chemical fingerprints?+
Yes. NEMS-FTIR is a bulk characterization method. The necessary sample preparation prior to analysis to minimize spectral interferences will depend on the nature of your sample.
Can I analyze volatile analytes with EMILIE?+
No. The EMILIE measurement chamber is evacuated down to a pressure of 10-3 to 10-5 mBar during measurements, which will cause volatile analytes to sublimate.
Can I analyze semi-volatile analytes with EMILIE?+
Yes. The EMILIE measurement chamber is evacuated down to a pressure 10-3 to 10-5 mBar during measurements. However, a Peltier element actively cools the EMILIE nanomechanical sensing chip during measurements to minimize evaporation and retain semi-volatile analytes on the surface.
Can I control the temperature of the EMILIE nanomechanical sensing chip during measurements?+
Yes. The temperature of the Peltier cooling element inside the EMILIE measurement chamber can be controlled from 0°C to 80°C. This feature can be used to retain semi-volatile analytes on the chip and perform temperature desorption experiments.
In which size range can EMILIE analyze nanoparticles?+
Emilie can be used to chemically characterize nanoparticles ranging from 10 nm to 1000 nm. It is recommended to filter out larger particles prior to analysis or during sampling to avoid damaging the nanomechanical sensing element.
In which wavelength range can EMILIE operate?+
EMILIE’s sensitivity is independent of wavelength, so you can use it over the entire infrared range, from near infrared to far infrared. The only limitation is your light source and optics. The EMILIE measurement chamber has a diamond window to provide the broadest possible range.
Will water cause spectral interferences?+
No. For nanoparticle dispersions, the nebulization sampling process will remove the water from your sample to deposit only the dry nanoparticles onto the EMILIE nanomechanical sampling and sensing chip. Other water-based samples can be deposited via drop-casting or dipping and allowed to dry prior to analysis. Additionally, NEMS-IR measurements with Emilie are recorded under vacuum so that no water vapour will interfere with your spectrum.
Can I use spectral features of the EMILIE nanomechanical sampling and sensing chip as an internal standard in quantitative methods?+
Yes. The Emilie nanomechanical sensing and sampling chip is made out of silicon nitride. It features a large absorption peak at 866 cm-1 which can be used as an internal standard.
How do I use my usual sampling system with the Emilie nanomechanical sampling and sensing chips?+
You can use our EMILIE sampling accessory to collect your aerosolized sample directly on the Emilie nanomechanical sampling and sensing chips.
What is the minimum amount of sample required to record a signal with Emilie?+
The detection limit will depend on the molar absorptivity of your sample. EMILIE has a limit of detection of a few picograms for caffeine when used in conjunction with a Quantum Cascade Laser (QCL) and up to a 100 pg when used in conjunction with a Fourier-Transform Infrared Spectrometer (FTIR).
What is the maximum amount of sample that I can put on Emilie?+
You can do quantitative work with samples in the range of a few picograms to approximately 50 ng, depending on your specific sample. Samples as large as several hundred nanograms can be analysed with EMILIE.
Do I need to know the concentration of my sample prior to analysis with Emilie?+
No. You can do quantitative work with EMILIE. However, the initial concentration of your sample will affect the sampling procedure. High concentrations can easily overload the chip and will need to be diluted or sampled for very short times. Very low concentrations of solutes in liquid samples will not be able to form large enough crystals during nebulization to be deposited effectively on the EMILIE nanomechanical sampling and sensing chip. In this case, other sample deposition techniques (drop casting, dipping,…) should be preferred. Very low concentrations of nanoparticles in the size range of 10-1000 nm (airborne or liquid dispersions) can be sampled via aerosol techniques without issue.
How long does it normally take to do one measurement?+
Measurements typically take approximately 5 minutes on an FTIR using the step scan mode and less than a minute with a Quantum Cascade Laser (QCL). Evacuation of the measurement chamber in between measurements takes a few minutes.