Teaching FT-IR spectroscopy with the ALPHA

Significance of the Topic

FT-IR spectroscopy is a versatile analytical technique widely used in chemistry education and research to characterize molecular vibrations and chemical bonding. Incorporating a compact, robust FT-IR spectrometer into teaching laboratories enhances hands-on learning by allowing students to perform real-world experiments on liquids, gases, and solids with high sensitivity and accuracy.

Objectives and Study Overview

This application note presents the use of the Bruker ALPHA FT-IR spectrometer as a teaching tool. It aims to demonstrate how the system’s compact design, accessory interchangeability, and guided software facilitate a range of standard teaching experiments covering quantification, polymer identification, and gas-phase rotational–vibrational spectroscopy.

Used Instrumentation

The Bruker ALPHA spectrometer features:

• A patented solid-state RockSolid interferometer and laser-aligned optics for high stability and accuracy
• User-replaceable infrared source and desiccant cartridge accessible from the instrument’s rear
• QuickSnap™ accessory exchange mechanism supporting transmission modules, ATR units, and gas cells without tools
• Compact footprint (7 kg) for placement in classrooms or gloveboxes, with wireless data communication capability

The accompanying teaching kit includes a liquid cell for Beer–Lambert experiments, a magnetic polymer foil holder with a dedicated library for thickness determination, and a gas cell with CaF2 windows for corrosive gases.

Methodology

The teaching kit is paired with a wizard-guided user interface and detailed manual describing standard experiments:

• Liquid-phase quantification of cyclohexanone in cyclohexane using Beer–Lambert laws
• Polymer foil identification via library search and thickness measurement from interference fringes
• High-resolution ro-vibrational spectroscopy of HCl vapor to resolve chlorine isotope splitting
• ATR measurements of air- and moisture-sensitive samples inside a glovebox using a platinum diamond ATR accessory

Main Results and Discussion

Example experiments demonstrated:

• Clear resolution of HCl ro-vibrational fine structure and isotopic splitting, illustrating rotational spectroscopy principles
• Quantitative determination of cyclohexanone concentration with reliable Beer–Lambert calibration
• Polymer foil library matching and thickness calculation from fringe patterns, reinforcing interferometry concepts
• Rapid identification of synthesized acetylsalicylic acid within seconds via automated library search (hit quality 940/1000)
• Seamless ATR analysis of air-sensitive compounds within a glovebox environment, highlighting ease of use with thick gloves and wireless data transfer

Students benefit from intuitive workflows that minimize setup time and allow focus on experimental interpretation.

Benefits and Practical Applications

The ALPHA system offers:

• Low operating costs due to long-life components and user-serviceable parts
• Robustness against mechanical shocks and external disturbances
• Flexibility through a range of easily interchangeable accessories
• Comprehensive teaching support with software wizards and detailed manuals

These features make the instrument suitable for undergraduate laboratories, advanced teaching courses, and routine research quality control.

Future Trends and Opportunities

Emerging developments may include:

• Expanded spectral libraries incorporating more specialized compounds (e.g., pharmaceuticals, polymers)
• Enhanced remote teaching capabilities via cloud-based data sharing and virtual lab simulations
• Integration with complementary techniques such as Raman or NIR spectroscopy for multi-modal analysis
• Advances in detector and source technology for increased sensitivity in trace analysis

Ongoing software improvements will further streamline data processing and interpretation for both educators and learners.

Conclusion

The Bruker ALPHA FT-IR spectrometer, together with its teaching kit and guided software, provides an effective platform for hands-on learning of infrared spectroscopy. Its combination of performance, portability, and user-friendly design supports a broad range of educational experiments while delivering reliable data required for both teaching and research contexts.

Reference

Bruker Optics. Application Note AN M88: Teaching FT-IR Spectroscopy with the ALPHA. 2021.