Fourier transform infrared (FTIR) spectroscopy is a flexible technique that may be used on various samples and in different scientific domains. The technology’s broad range of capabilities also includes a diverse set of methodologies, components, and features from which to pick. You may require different sample handling methods, modules, and equipment to provide the best outcomes for a given sample in a given application. Utilize this guide to assist narrow down the top solutions for your lab, samples, and applications while examining the enormous diversity of accessible FTIR sample handling solutions available at a website such as Agilent FTIR spectroscopy instruments.

  1. Attenuated total reflectance

Because of its ease of usage and adaptability to a wide range of sample varieties, comprising hard solids, powders, liquids, and even tough, thick, and intensely absorbent substances like black rubber, attenuated total reflectance (ATR) is the most popular sample handling approach for FTIR spectroscopy. This method uses a crystal with a specific shape and refractive index that creates an evanescent wave that impacts the sample in contact with the surface of the crystal when struck by IR radiation. The beam is attenuated where the sample absorbs energy and departs the other end of the crystal prior to hitting the detector.

Because you may put the sample directly on the crystal surface provided a sufficient surface area is in contact with the crystal surface, this approach needs very little if any sample preparation. Although you can utilize bigger samples, the procedure only requires tiny sample quantities to encompass the crystal surface. The ATR technique is a reliable alternative for the majority of the cases if you wish to cut down on prep time and are dealing with a wide variety of solid, liquid, organic, and inorganic samples or extremely absorbent substances. However, because of the expense of the crystal attachments, ATR might be more expensive than other procedures; therefore, it is not utilized for gas analysis. 

  1. Transmission

Most spectrum libraries have been created using the straightforward, classic approach of transmission FTIR spectroscopy, whereby the sample is put right in the path of the IR beam. Although it is no longer as popular as ATR, most labs still employ it because it produces high-quality qualitative and quantitative findings at a lesser cost than most other techniques. When sample preparation isn’t done correctly and consistently, the method’s reproducibility will also decrease.

Transmission may be the ideal approach for your lab if you need to conserve money, and it delivers good sensitivity and high-quality spectra with adequate sample prep. It also has the benefit of a large number of well-established reference libraries.

  1. Reflectance-absorbance

The most typical use of IR reflectance-absorbance spectroscopy (IRRAS) is to examine a thin layer of material on a flat reflecting surface, such as metal. The IR beam travels through the sample at a precise angle, reflects off the substrate, and then goes back through the sample before hitting the detector in this approach. Based on the angle of the beam, this approach is non-destructive and can detect incredibly thin layers and monolayers. While minimal sample preparation is required, extra accessories you can acquire from dealers like Agilent FTIR spectroscopy instruments are needed to achieve the grazing angle and sensitivity needed to evaluate exceedingly thin sample layers.

FTIR is among the most reliable and effective technologies available for monitoring objectives. Furthermore, its flexibility and responsiveness make it a cost-effective and versatile tool for measuring various samples.