Fourier Transform Infrared Spectroscopy (FTIR) Analysis: Principles, Techniques, and Applications
Fourier Transform Infrared Spectroscopy (FTIR) is one of the most versatile analytical techniques available for material identification, chemical analysis, and quality control. By measuring how materials absorb infrared radiation at specific wavelengths, FTIR reveals molecular composition and chemical bonding information that is unique to each substance. FTIR serves critical roles in the plastics, pharmaceutical, chemical, automotive, forensic, and environmental industries. For companies seeking FTIR analysis at a US-based testing lab, Infinita Lab provides comprehensive spectroscopic analysis through its accredited laboratory network.
How FTIR Works
FTIR instruments direct broadband infrared light through an interferometer onto the sample. Different molecular bonds absorb specific IR wavelengths based on their vibrational frequencies, producing a unique absorption spectrum—the material’s molecular fingerprint. The Fourier transform algorithm converts the raw interferogram into a frequency-domain spectrum that is compared against reference libraries for identification.
Common FTIR Sampling Techniques
Attenuated Total Reflectance (ATR)
ATR is the most widely used FTIR technique and requires minimal sample preparation. The sample is pressed against a crystal (diamond, germanium, or ZnSe), and the IR beam penetrates a few microns into the surface. ATR rapidly and non-destructively analyzes solids, liquids, powders, films, and coatings.
Transmission Mode
IR light passes directly through thin film or KBr pellet samples. Transmission provides the highest spectral quality and is used for quantitative analysis, gas analysis, and reference spectrum generation.
FTIR Microscopy
Combining FTIR with optical microscopy enables chemical mapping of microscopic features—contaminant particles, coating layers, fiber cross-sections, and interfacial chemistry — in the semiconductor and forensic analysis fields.
Industry Applications of FTIR
FTIR applications include polymer identification and additive analysis for the plastics industry, pharmaceutical raw material verification (USP <197>), contamination identification and failure analysis, coating and adhesive chemistry characterization, environmental analysis (gas emissions, water contaminants), and food safety testing for adulterant detection.
Key Testing Standards
Standards include ASTM E168 (general FTIR practices), ASTM E1252 (qualitative analysis), ASTM D5576 (polyethylene identification), ASTM D5477 (FTIR for polymers), USP <197> (pharmaceutical IR identification), and ISO 10640.
Partnering with Infinita Lab for Optimal Results
Infinita Lab addresses the most frustrating pain points in the FTIR Analysis testing process: complexity, coordination, and confidentiality. Our platform is built for secure, simplified support, allowing engineering and R&D teams to focus on what matters most: innovation. From kickoff to final report, we orchestrate every detail—fast, seamlessly, and behind the scenes.
Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote
Frequently Asked Questions (FAQs)
What does FTIR analysis identify? FTIR identifies materials by their molecular composition—revealing polymer type, chemical functional groups, additives, contaminants, and degradation products. Each material produces a unique infrared absorption spectrum.
What is ATR-FTIR? ATR (Attenuated Total Reflectance) is an FTIR sampling technique where the sample contacts a crystal surface. It requires minimal preparation and analyzes solids, liquids, and powders quickly—making it the most common FTIR method.
What ASTM standards apply to FTIR analysis? ASTM E168 covers general practices, ASTM E1252 covers qualitative analysis, ASTM D5576 covers polyethylene identification, and ASTM D5477 covers polymer analysis by infrared spectroscopy.
Can FTIR identify unknown contaminants? Yes, FTIR is one of the primary tools for contaminant identification in failure analysis. The absorption spectrum is compared against libraries containing thousands of reference materials to identify unknown substances.
What sample types can FTIR analyze? FTIR analyzes virtually any sample type—solids, liquids, gases, powders, films, fibers, coatings, and microscopic particles. ATR-FTIR requires no sample preparation for most materials, while transmission mode requires thin films or pellets.
