Which Spectroscopy Method Should You Use?
Choosing between FTIR, Raman, NIR, UV-Vis, and SERS depends on your sample, your question, and your budget. Use the interactive wizard below to get a personalized recommendation, or browse the full comparison matrix and technique deep dives.
Find Your Ideal Technique
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What are you trying to do?
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Technique Comparison Matrix
Side-by-side comparison of all five spectroscopy modalities.
| Feature | FTIR | Raman | NIR | UV-Vis | SERS |
|---|---|---|---|---|---|
| Information type | Molecular vibrations (IR active) | Molecular vibrations (Raman active) | Overtones & combinations | Electronic transitions | Enhanced Raman |
| Sample prep | KBr pellet, ATR, transmission | Minimal — point and shoot | Minimal | Dissolve in solvent | Nanoparticle substrate |
| Water compatible | Poorⓘ | Excellentⓘ | Poorⓘ | Goodⓘ | Goodⓘ |
| Spatial resolution | ~10 μm (microscope) | ~1 μm (confocal) | ~25 μm | N/A (bulk) | Nanoscale |
| Depth of analysis | Surface (~1–5 μm ATR) | Bulk (mm penetration) | Bulk (mm) | Bulk (path length) | Surface (nm) |
| Quantitative | Good (Beer-Lambert) | Moderate | Excellent | Excellent | Poor |
| Cost (entry-level) | $20K–$40K | $40K–$100K | $30K–$60K | $5K–$15K | $50K+ |
| Speed | 30s–2min | 10s–5min | 1s–30s | 1s–10s | 10s–5min |
| Sensitivity | ppm–% | ppm–% | 0.1–100% | ppb–ppm | ppb–ppt |
| Complementary to | Raman | FTIR | FTIR, UV-Vis | NIR, FTIR | Raman |
Technique Deep Dives
Expand each modality for detailed guidance on when to use it.
Frequently Asked Questions
When should I use FTIR vs Raman spectroscopy?
FTIR and Raman are complementary techniques — both probe molecular vibrations but by different mechanisms. Use FTIR when you need well-established databases for organic identification, Beer-Lambert quantitation, or when budget is a factor ($20K–$40K vs $40K–$100K for Raman). Choose Raman when you need minimal sample prep, water compatibility, or high spatial resolution (~1 μm confocal). Many labs use both: FTIR for routine QC and Raman for problem-solving.
Which spectroscopy method is best for polymers?
FTIR with ATR (attenuated total reflectance) is the gold standard for polymer identification. Every polymer has a unique IR fingerprint, and ATR requires zero sample preparation — just press the sample against the crystal. Raman is a strong second choice, especially useful for polymers that are heavily filled or in aqueous environments. NIR is preferred for quantitative analysis in polymer manufacturing (e.g., composition or moisture content) when paired with chemometric models.
What is the cheapest spectroscopy technique?
UV-Vis spectroscopy has the lowest entry-level cost at $5K–$15K for a basic spectrometer. FTIR instruments start at $20K–$40K, NIR at $30K–$60K, and Raman at $40K–$100K. SERS requires specialized substrates on top of a Raman instrument ($50K+). For students and teaching labs on a tight budget, UV-Vis is the most accessible option while still providing excellent quantitative capabilities.
Can I analyze aqueous samples with spectroscopy?
Raman spectroscopy is the best choice for aqueous samples because water is a very weak Raman scatterer. UV-Vis also works well since water is transparent above ~190 nm. FTIR and NIR are poor choices for aqueous work because water absorbs strongly in the infrared, masking analyte signals. SERS can work in aqueous environments with proper nanostructured substrates.
What spectroscopy technique has the best sensitivity for trace analysis?
SERS (surface-enhanced Raman spectroscopy) offers the highest sensitivity, detecting analytes at parts-per-trillion (ppt) levels — even single molecules in some cases. UV-Vis provides ppb–ppm sensitivity for absorbing species. Standard FTIR and Raman typically detect at ppm to percent levels. NIR is the least sensitive (0.1–100% range) but excels at quantitative analysis of major and minor components.
Which spectroscopy method requires the least sample preparation?
Raman spectroscopy requires the least sample preparation — simply point the laser at your sample. It works through glass, plastic packaging, and even underwater. NIR is also minimal-prep for solids and powders. FTIR-ATR has become nearly as convenient, requiring only that the sample contacts the crystal. UV-Vis typically requires dissolving the sample. SERS requires the most preparation (fabricating or applying nanostructured substrates).
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