How IR Spectrometers Work & How We Save You Time & Money

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Infrared spectroscopy instrumentation

Infrared spectroscopy describes the interaction of infrared radiation (IR) with matter.

Spectroscopy diagram

More specifically, it is a spectroscopic technique used to identify and study inorganic and organic compounds based on their light absorption in the IR spectrum. Depending on which type of spectrometer you use, the technique detects photons that are transmitted, absorbed, or reflected when a sample is excited using IR light. The chemicals studied can be in solid, liquid, or gas forms.

The infrared region of the electromagnetic spectrum has longer wavelengths and a lower frequency than visible light, making it more suitable for molecular vibration studies. This spectrum is usually divided into three regions: the near-infrared, mid-infrared, and far-infrared, and are named for their relation to the visible spectrum.

While spectroscopy, as a whole, is the study of interactions between matter and radiated energy, spectrometry is the method used to acquire a quantitative measurement. In other words, actually collecting data is made possible with a spectrometer. In the case of IR spectroscopy, an IR spectrometer is used.

Today, one of the most common types of IR spectrometers today is the Fourier-transform infrared spectrometer (FTIR), which employs an interferometer rather than a dispersive monochromator. An FTIR spectrometer produces an infrared spectrum using a broadband IR light source that illuminates the sample. It is eventually visualized as a graph by measuring infrared light absorption and the frequency or wavelengths on their respective axes.

IR spectroscopy relies on the fact that molecules absorb frequencies in a way that is characteristic of their unique structures. This includes the resonant frequencies of each chemical. The absorbed radiation matches the vibrational frequency, which occurs because the energies are affected by the masses of the atoms, the unique shapes of the molecular potential energy surfaces, and the vibronic coupling.

For a sample to be considered IR active, it needs to experience changes in the dipole moment. This refers to vibrational modes, which are a measure of vibrational freedom that varies with the number of atoms and whether the structure is linear or nonlinear.
Other applications of IR spectroscopy, other than organic and inorganic R&D, include chemical analysis, environmental testing, and forensics, which we will cover briefly below.

Uses, Benefits, & FTIR Spectrometer Device Cost

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IR spectroscopy is complex. However, its practical uses are plenty. Due to their usefulness, these devices can be of immense help to organic and inorganic chemists, as well as a wide variety of scientists and researchers in the life sciences.

Below, we will cover some of the most common analytical uses for infrared spectroscopy and briefly review the basic instrumentation of the IR spectrometer.

Spectrometer Instrumentation

FTIR spectrometers are the most common types of IR spectrometers. They are extremely useful, but how they work isn’t always intuitive. Understanding the various uses of these devices can help you maximize their use. There are three main things you should know:

  • FTIR: Fourier transform infrared spectroscopy is a specific measurement technique that allows for recording within the infrared spectra. This is completed by guiding the light through the sample and an interferometer. The signal is read and notated to the interferogram. The data is then processed using the Fourier transform method turning it from raw data into the result, light as a function of IR wavelength.
  • Sample Preparation: Preparing samples is dependent on the state that it is in. Gaseous samples are often placed in test tubes with transparent windows. Liquid samples are placed between two plates of sodium chloride. Solid samples have more options, sometimes being crushed into an oily mulling agent, other times being ground with a sample of purified salt, and occasionally dissolving the sample into a solvent and then evaporating it.
  • Reference Comparison: When performing this technique, it is normal to record the sample’s spectrum and a reference. This helps control for several variables, especially instrument influence.

Another type of IR spectrometer is available, which employs a different kind of spectroscopy: dispersive absorption IR spectroscopy.

The first IR spectrometers, developed in the mid 1940s, used dispersive absorption spectroscopy, which differed from FTIR (FTIR wouldn’t be developed until the 1960s) in that dispersive IR is a type of grating spectrometry. It gives spectra of different orders directly. On the other hand, FT-IR requires processing and is an indirect way to obtain the same spectra.

These early spectrometers use an IR source and lenses. However, the similarities between them and modern spectrometers end there. The bigggest difference is that an FTIR spectrometer uses an interferometer, rather than a monochromator, to detect all wavelengths simultaneously.

FTIR spectrometers provide more advantages than dispersive absorption instruments, which have made them the go-to spectrometer in modern labs. These devices offer improved signal-to-noise ratio, spectral quality, data collection speed, reproducibility, and ease of use. Most IR spectroscopy instruments available today rely on FTIR.

Organic & Inorganic Chemistry

IR spectroscopy offers reliable techniques for inorganic and organic chemistry applications, whether research-oriented or industrially related. Everything from monitoring applications, dynamic measurements, and even quality control can benefit from this technique.

Forensic Analysis

Forensic analysis also uses this technique in both criminal and civil cases. Polymer degradation is a standard application in this field and is often used when determining the blood alcohol content of people suspected of driving while drunk.


Quantifying polymer degradation is also applicable in a manufacturing setting. This is used to determine the degree of polymerization in polymer manufacturing. Measuring the bond at a specific frequency over a period of time makes changes more visible and increases the speed and accuracy at which chemical reactions are observed.


Microelectronics can utilize this technique to analyze semiconductors such as silicon, gallium nitride, zinc selenide, gallium arsenide, amorphous silicon, silicon nitride, and other materials.

Infrared Radiation & NASA

As of 2014, even NASA utilizes IR spectroscopy to track polycyclic aromatic hydrocarbons (PAHs) in the universe. PAHs may be related to more than 20% of all the carbon in the universe and could be the basis for the formation of life after the Big Bang.

Vibrational Spectroscopy System Leases to Fit Every Need

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Founder-Friendly Leases

Our lease agreements are founder-friendly and flexible, helping you preserve working capital, strengthen the cash flow of your business, and keep business credit lines open for expansions, staffing, and other crucial operational expenses and business development opportunities.

2-5 Year Lease Lengths

Leases range from 2 to 5 years. Length will depend on several factors, including how long you want to use the equipment, equipment type, and your company’s financial position. These are standard factors leasing companies consider and help us tailor a lease agreement to fit your needs.

Your Choice of Manufacturer

We don’t carry an inventory. This means you’re not limited to a specific set of manufacturers. Instead, you can pick the equipment that aligns with your business goals and preferences. We’ll work with the manufacturer of your choice to get the equipment in your facility as quickly as possible.

Maintenance & Repair Coverage

Bundle preventive maintenance and repair coverage with your lease agreement. You can spread those payments over time. Easily maintain your equipment, minimize the chances something will break down, repair instrumentation quickly, and simplify your payment processes.

End-of-Lease Options

At the end of your lease, you have multiple options. You can either renew the lease at a significantly lower price, purchase the machine outright based on the fair market value of the original pricing, or call it a day and we’ll come the pick up the equipment for you free of charge.

No Loan-Like Terms

Our leases do not include loan-like terms, which can be restrictive or harmful in certain situations. We do not require debt covenants, IP pledges, collateral,  or equity participation. Our goal is to maximize your flexibility. When you lease with us, you’re collaborating with a true business partner.

In-House Underwriting Process

Our underwriting is done in-house. You can expect quicker turnaround, allowing you respond to your equipment needs as they arise. We require less documentation than traditional lenders and financiers and can get the equipment you need in operation more quickly.

Popular Infrared Spectrometer Manufacturers

Buck Scientific
Perkin Elmer
Thermo Fisher Scientific