Understanding the noise of a measurement
Signal to noise is an important topic when discussing the performance of a spectrometer and a convenient way to describe this is through Allan deviation, which provides a way to quantify the noise present in a system as a function of integration time. ... Continue reading
Highly spatially resolved (~15µm) measurements with the IRis-F1
The IRis-F1 is a laser-based instrument whose beam can be tightly focused, so it is well-suited to measuring small features. This application note shows how the IRis-F1 can be used to perform microscopy.... Continue reading
Photophysics of Metal Complexes: Reaching a Time Resolution of 250 ns
In 2020 we had the opportunity to visit the research labs of Prof. Markus Gerhards at the Technical University of Kaiserslautern and to work with him and his team. We were in the process of setting up a collaboration, when Prof. Gerhards tragically and unexpectedly passed away. Sadly, we never finished some the most exciting parts of our project, however, during our initial visit we acquired data on a pair of transition metal complexes, which we would like to present here.... Continue reading
Diffuse Reflectance Infrared Comb Spectroscopy (DRICS) with microsecond resolution
Although many chemists and chemical engineers work in the solution phase, a vast number of reactions occurring in nature and in industry happen between phases, that is, they are heterogeneous. For catalytic reactions, if the catalyst is in a different phase to the reagent, the process is known as heterogeneous catalysis.... Continue reading
Diffuse reflectance dual comb mid-IR spectroscopy for heterogeneous catalysis
Heterogeneous catalysis is an extremely important field of research, underpinning many industrial processes. It is defined by catalysts that are in a different phase to the reaction materials with which they interact, for example, a solid catalyst interacting with liquid or gaseous reagents. This is attractive from a processing perspective because catalysts and products can easily be separated. It also means that reactions typically occur on surfaces or interfaces.... Continue reading
Mid-IR PAT with 10 meter fiber probes
Fiber optics, coupled to an ATR probe are often used in combination with infrared spectroscopy for industrial reaction monitoring purposes. While fibers in the visible and near-IR spectral regions can have a length of many tens or even hundreds of meters, mid-IR fiber technology is more limited. Even the leaders in mid-IR fibers typically provide only 2-4 m long fiber probes, as the attenuation at longer distances is simply too great for them to be used with commercial FTIR spectrometers. A solution to this limitation is to increase the power of the spectroscopic light source. ... Continue reading
Millisecond protein kinetics studied by stopped-flow with mid-IR dual comb spectroscopy
Following kinetics with mid infrared (mid-IR) spectroscopy allows protein chemists to better understand how proteins fold and to obtain information about secondary structure changes involved in the folding process. Stopped-flow is a popular technique for these studies where reagents are rapidly mixed and the consequent reactions can be studied with few milliseconds dead time... Continue reading
Infrared stopped-flow at 220 spectra per second: a new addition to the toolbox
This application note explores the use of the IRis-F1 spectrometer in infrared stopped flow experiments. First we investigate the hydrolysis of methyl chloroacetate (MCA) and this will be followed by the refolding of ubiquitin, which is expected to be a more challenging measurement. ... Continue reading
Dental curing
Adhesives and fillings employed in dentistry are expected to handle many years of physical stress, be non-toxic and easily applied in a pain-free and convenient manner. On top of this, they are expected to solidify and set at exactly the right time. Photochemistry is the method of choice for this, to ensure that the curing process can be triggered exactly when wanted. ... Continue reading
Stopped flow as a way to study chemical reactions
Understanding the mechanism of a chemical reaction is a first step away from trial-and-error-based optimization. By studying the structures of intermediates, for how long they exist, and the ways in which they can and cannot react, reactions can be intelligently designed and controlled.... Continue reading
Blending: active pharmaceutical ingredients quantification
One of the current challenges in the pharmaceutical industry is the reliable quantification of Active Pharmaceutical Ingredients (APIs) in a substrate. Optical spectroscopy is a preferred method in this application due to its simplicity. However, at low API concentrations, the sensitivity of current FTIR-based equipment is not sufficient. The dual-comb spectrometer IRis-F1 provides a solution, exploiting the high brightness of the laser source for increased signal-to-noise ratio.... Continue reading
Rapid reaction monitoring of curing processes with the IRis-F1
Fast spectroscopic monitoring is a proven tool in R&D and production environments, where it is used to gain insight into chemical reactions. This application note showcases how the IRis-F1 dual-comb spectrometer (DCS) can be used to monitor curing reactions, where it can provide invaluable insight on the performance of coatings and adhesives. Infrared spectroscopy is in... ... Continue reading
Measurement of optically dense samples with the IRis-F1
There are several reasons why users may want to measure infrared spectra of optically dense samples or on strongly absorbing backgrounds. For instance, scientifically relevant samples in heterogeneous catalysis or biology often consist of an analyte embedded in a complex matrix. Removing the analyte from this matrix to make it amenable to spectroscopic investigations can alter its behavior. ... Continue reading
Resolution vs point spacing
Understanding of the terms spectral resolution and spectral sampling may sometimes lead to confusion. This is due to the fact that very often, especially when talking about FTIR spectrometers, these two parameters are used interchangeably. And such use is misleading. We provide here the explanations of these quantities. Spectral resolution is the wavenumber, wavelength or frequency... Continue reading