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What Raman & Infrared Spectroscopy got wrong, from 46 theses
Summary written by a model from the records below: The records document technical limitations and experimental bottlenecks encountered when applying Raman and infrared spectroscopy across diverse materials and biological samples. Key recurring difficulties include overwhelming background interference from fluorescence or water, low analyte concentrations below detection thresholds, and chemometric modeling errors. These records come from graduate theses, 2021 to 2026, each labeled with its degree where the repository states it, and each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Plus 7 problems the authors left open, listed at the end.
Failure modes, by theses reporting them
Select a mode to jump to its records.
Low analyte concentrations and weak scattering cross sections fall below detection limits
Target analytes present at trace levels or low abundances fail to produce distinguishable spectral features above detector noise or substrate backgrounds. Unenhanced Raman and infrared measurements frequently lack the sensitivity or cross section needed to detect subtle structural defects or minor phases.
Tried and failed
Raman spectroscopy for defect detection applied to sub-nanometer defects in 2D materials. Outcome: no signal. Reason: optical measurement lacked sensitivity to detect sub-nanometer atomic defect formation across ion doses
Low-Dimensional Material Devices For Atomic Defect Engineering, Ionic And Molecular Transport · Penn · PhD
Tried and failed
unenhanced Raman spectroscopy with long acquisition times applied to low-concentration bacterial pathogen classification. Outcome: no signal. Reason: signal intensity at clinically relevant low concentrations was insufficient without enhancement despite prolonged integration
Raman spectroscopy for point of care urinary tract infection diagnosis · Imperial · PhD
Tried and failed
blind source separation on mixture spectra applied to low-intensity component identification. Outcome: no signal. Reason: low Raman scattering intensity prevented detection without artificial 100-fold amplification of its reference spectrum
Development of In Situ Monitoring and Data-Driven Modeling for Complex Systems: Case Study on Simulant Mixtures of Nuclear Waste · Georgia Tech · PhD
Tried and failed
low-power ambient Raman spectroscopy for phase detection applied to biphasic fluid inclusion density measurements. Outcome: no signal. Reason: low power and ambient temperature fail to detect small coexisting liquid volumes near the vapor boundary
MAGMATIC DRIVERS OF EXPLOSIVE VOLCANISM: INSIGHT FROM MAGMA MIXING, MELT INCLUSIONS AND RAMAN SPECTROSCOPY · Cornell · PhD
Tried and failed
785 nm Raman spectroscopy applied to detecting high-wavenumber O-H stretching bands. Outcome: no signal. Reason: low quantum efficiency of silicon CCD detectors near the bandgap cutoff wavelength
Advanced applications of Raman spectroscopy and machine learning techniques · Iowa State · PhD
Tried and failed
Raman spectroscopy for organic detection applied to mineral precipitate coprecipitation samples. Outcome: no signal. Reason: Organic concentrations sufficient for mineral stabilization fell below the detection limit of Raman spectroscopy.
Organic influences on hydrated magnesium carbonate mineral formation · MIT · PhD
Considered and rejected
Considered and rejected: Dismissed solid-phase FTIR and Raman spectroscopy for detecting low-level auxotrophic UAA incorporation due to insufficient sensitivity and signal attenuation
An interdisciplinary approach for developing novel methods to study silks · Oxford · PhD
Tried and failed
visible-near-infrared spectroscopy with partial least squares regression applied to low-concentration iron compounds in soil. Outcome: no signal. Reason: insufficient spectral sensitivity and absorption feature definition at low analyte concentrations (0–5000 mg/kg)
Evaluation and adaptation of portable x-ray fluorescence and data fusion techniques for non-invasive characterisation of metal-contaminated environments · Cranfield · PhD
Tried and failed
visible and near-infrared reflectance spectroscopy applied to subsurface sediment mobilization landforms. Outcome: no signal. Reason: Spectra lacked diagnostic absorption features required to identify expected alteration minerals like phyllosilicates, carbonates, or sulfates
Subsurface Sediment Mobilization on Mars: Insights Provided by Orbital Remote Sensing Datasets · Georgia Tech · PhD
Tried and failed
surface-enhanced Raman spectroscopy on precursor controls applied to isolated nanoparticle precursor mixtures. Outcome: no signal. Reason: isolated precursors or bare nanoparticles lacked sufficient cross-section or enhancement to produce detectable spectral signals
Advances in optical trapping beyond biophysics: combining force and optical spectroscopies under diverse chemical conditions · Boston University · PhD
Tried and failed
surface-enhanced Raman spectroscopy single-peak detection applied to sub-nanomolar analyte concentration sensing. Outcome: no signal. Reason: insufficient spectral changes at low nanomolar concentration thresholds for single-peak spectral analysis
Polypyrrole-coated gold nanoflowers as multifunctional nanoparticles for cancer theranostics · Imperial · PhD
Tried and failed
density separation and micro-FTIR spectroscopy applied to marine sediment core microplastic extraction. Outcome: no signal. Reason: Target particles were below detection limit or completely absent in specific sediment depth layers
Investigation of Microplastics from Deep-Sea Antarctic and West Coast North American Sediments · Harvard · Master's
Tried and failed
ATR-FTIR spectroscopic imaging applied to identifying inorganic degradation products. Outcome: no signal. Reason: vibrational modes of these inorganic species lacked sufficient infrared activity or distinct absorption bands within measured range
Applications of advanced atr-ftir spectroscopic imaging to objects of cultural heritage · Imperial · PhD
Chemometric and deconvolution models fail to classify or quantify spectral mixtures accurately
Automated classifiers and regression methods yield prediction errors that exceed target boundaries or misclassify samples relative to simpler baselines. Spectral deconvolution algorithms also perform poorly when components lack sufficient degrees of freedom or when features vary predominantly in amplitude rather than position.
Lost to a baseline
Simulated in-line Raman DBC had 16.98% %CV relative to UV chromatograms, underperforming HPLC (1.25% %CV) and well-plate Raman (1.99% %CV).
Monitoring of biotherapeutic purification by vibrational spectroscopy · Imperial · Doctorate
Lost to a baseline
Visual spectral comparison correctly differentiated inkjet Raman spectra via 1-3 minor peaks where automated LDA classifiers (PCA-LDA, PLS-DA, Sparse LDA) produced concordant misclassifications.
DEVELOPMENT AND VALIDATION OF A TECHNIQUE FOR ANALYSIS OF TONER PRINTED DOCUMENTS USING MAGNETIC FLUX MEASUREMENTS · Sam Houston State University · PhD
Lost to a baseline
HPLC was far more specific and accurate than handheld NIR and Raman spectroscopy, which produced false positive flags on authentic/compliant high-dose formulations.
RETROSPECTIVE DESCRIPTIVE STUDY ON POST-MARKET MEDICINE QUALITY-RELATED COMPLAINTS AND THE APPLICATION OF FIELD-BASED DETECTION OF POORQUALITY MEDICINES USING NEAR-INFRARED AND RAMAN SPECTROSCOPIC SCREENING METHODS · De Montfort University · PhD
Tried and failed
partial least squares regression on infrared spectra applied to narrow continuous ratio class boundaries. Reason: prediction error exceeded the width of the target classification intervals
A soil organic carbon indexing and measurement system · Cranfield · PhD
Tried and failed
multiple linear regression spectral deconvolution applied to surface-enhanced infrared absorption spectra. Reason: displaced solvent background interference and optical grating-order shifts created false negative concentration signals
Tried and failed
applying identical line-mixing models across polarization components applied to high-pressure ro-vibrational Raman spectroscopy thermometry. Reason: anisotropic transitions do not undergo line mixing identically to isotropic transitions, causing systematic temperature error
Thermometry in high pressure gases using spontaneous Raman scattering · UT Austin · PhD
Lost to a baseline
Raman spectral imaging was marginally less precise than FT-IR in recognizing dairy residue products (accuracy of 97.51% with 14 LVs vs 98.73% with 5 LVs, respectively).
Multiscale spectral imaging for food safety with relevance to dairy processing · University College Dublin · PhD
Considered and rejected
Considered and rejected: Rejected single-modality spectroscopy in favor of mid-level data fusion because individual Vis-NIR (85.8%) and Raman (87.3%) models yielded inferior classification compared to fused data (92.8%).
Signature of Irish grass-fed beef - Authentication of the dietary background and geographical origin of Irish grass-fed beef using chromatographic and rapid spectroscopic techniques integrated with chemometrics · University College Dublin · PhD
Tried and failed
two-component spectral deconvolution modeling applied to mixed-phase infrared absorption spectra. Outcome: worse than baseline. Reason: two components lacked sufficient degrees of freedom to capture the observed multi-phase spectral variations
Infrared Spectroscopy at Three and Six Microns of Water Ices Mixtures of Astrochemical Interest · Georgia Tech · PhD
Tried and failed
multiphase spectral deconvolution applied to infrared vibrational absorption bands. Outcome: no signal. Reason: the spectral feature varied predominantly in amplitude rather than shape or position across phases
Infrared Spectroscopy at Three and Six Microns of Water Ices Mixtures of Astrochemical Interest · Georgia Tech · PhD
Lost to a baseline
Quantitative dispersion spectroscopy RMSEC for Glucose (0.17 g L-1) was beaten by direct absorption spectroscopy RMSEC (0.05 g L-1)
Advances in mid-infrared dispersion spectroscopy of liquids and photothermal gas sensing · TU Wien · PhD
Spectral interference from substrates, containers, and matrix components obscures target peaks
Spectroscopic measurements frequently suffer from intense vibrational signatures introduced by glass containers, mounting substrates, paraffin fixatives, or immersion oils. Adsorbed surface contaminants and complex biological or dietary backgrounds introduce overlapping bands that mask the diagnostic peaks of target compounds.
Tried and failed
membrane filtration surface-enhanced Raman spectroscopy applied to clinical biofluid pathogen detection. Outcome: no signal. Reason: detector saturation and spectral interference from background particulate matter in unpurified samples
Raman spectroscopy for point of care urinary tract infection diagnosis · Imperial · PhD
Tried and failed
Raman spectroscopy for tracking molecular doping levels applied to organic hole transport materials. Outcome: no signal. Reason: overlapping vibrational peaks between neutral molecules and polaronic charged states prevented distinction
Organic and hybrid semiconductors for photovoltaic application — control of energetics and interfacial properties · Imperial · PhD
Tried and failed
Handheld Raman spectroscopy through glass containers applied to pharmaceutical powder in glass vials. Outcome: no signal. Reason: Container optical interference and dispersed powder prevented distinguishable spectral signal from empty vials
New Tools for Rapid Mass Spectrometric Screening · Georgia Tech · PhD
Considered and rejected
Considered and rejected: Rejected paraffin embedding because paraffin-derived Raman bands interfered with subtle plasma-induced spectral alterations
Considered and rejected
Considered and rejected: Rejected using oil immersion lenses to improve Raman depth resolution because immersion oils introduce interfering spectral peaks that mask weak protein signals.
Monitoring of biotherapeutic purification by vibrational spectroscopy · Imperial · Doctorate
Tried and failed
stimulated Raman scattering unmixing microscopy applied to organism digestive tract quantification. Outcome: no signal. Reason: ingested dietary material produced broad, highly variable interfering background signals
Chemical microscopy and image analysis for biomedical applications · Harvard · PhD
Considered and rejected
Considered and rejected: Rejected analyzing single-crystal Raman spectroscopy for bulk CoSb3 due to persistent surface Sb flux signals, choosing polycrystalline samples instead.
Considered and rejected
Considered and rejected: Rejected silicon and quartz substrates for Raman spectroscopy because substrate background signals obscured PVAL vibrational bands, adopting gold-sputtered glass SERS substrates instead.
Deciphering the influence of local chain order on thermal transport in macromolecular matter · Imperial · PhD
Tried and failed
single-point ATR-FTIR spectroscopy applied to surface-contaminated microplastics. Outcome: no signal. Reason: adsorbed chemical contaminants obscured surface spectra causing unmatchable spectra or false compound identifications
Microplastics in Wastewater Treatment Plant Sludges: Detection Methods, Seasonal Variation, and Effects on Anaerobic Digestion · Carleton University · PhD
Severe fluorescence and photoluminescence backgrounds overwhelm characteristic Raman signals
Excitation lasers stimulate strong fluorescence and photoluminescence emission from organic matter, trace impurities, and narrow-bandgap materials. This intense background radiation floods the detector and completely obscures weak characteristic Raman peaks.
Tried and failed
visible laser Raman spectroscopy applied to ionic liquids. Reason: strong temperature-dependent fluorescence background obscured the Raman signal
Advanced applications of Raman spectroscopy and machine learning techniques · Iowa State · PhD
Tried and failed
785 nm Raman spectroscopy applied to mineral phases in cementitious materials. Outcome: no signal. Reason: Photoluminescence from trace rare earth impurities overlapped and obscured characteristic Raman peaks
Assessing long-term carbonation resistance of blended concretes from short-term natural exposure · Imperial · PhD
Tried and failed
confocal Raman micro-spectroscopy applied to aged concrete binder phases. Outcome: no signal. Reason: impurity fluorescence overwhelmed and obscured weak characteristic Raman signals
Time-Space-Resolved Raman Analysis of Structure-Property Relationships in Heterogeneous Structural Materials · MIT · PhD
Tried and failed
1H NMR and Raman spectroscopic characterization applied to purified carbon dots. Outcome: no signal. Reason: insolubility, strong fluorescence background interference, and low mass yields
Unraveling the fluorescence puzzle: examining the role of purification and passivation in carbon dots · Imperial · Doctorate
Tried and failed
Raman spectroscopy applied to immature organic biological tissues. Outcome: no signal. Reason: Strong fluorescence background from high organic content overwhelmed the Raman signal
Time-Space-Resolved Raman Analysis of Structure-Property Relationships in Heterogeneous Structural Materials · MIT · PhD
Tried and failed
direct unenhanced Raman spectroscopy applied to clinical urine specimens. Outcome: no signal. Reason: broad biochemical variability and high fluorescence background masked diagnostic spectra
Raman spectroscopy for point of care urinary tract infection diagnosis · Imperial · PhD
Considered and rejected
Considered and rejected: Rejected using 1H NMR and Raman spectroscopy for MCD characterization due to poor solvation signal, background fluorescence, and excessive required sample mass.
Unraveling the fluorescence puzzle: examining the role of purification and passivation in carbon dots · Imperial · Doctorate
Considered and rejected
Considered and rejected: Selected a higher 4 mW laser power over a 0.8 mW setting for Raman spectroscopy because 0.8 mW yielded small, broad peaks obscured by strong fluorescence background, despite 4 mW inducing sample degradation upon repeat exposures.
The atmospheric entry of micrometeorites on Mars: Implications for their mineralogy, texture and organic constituents · Imperial · PhD
Considered and rejected
Considered and rejected: Spatial Heterodyne Raman Spectroscopy (SHRS) rejected for biological and highly fluorescent samples due to excitation wavelength limitations and single-channel constraint
Chemical Sensing as a Utility using Swept-Source Raman Spectroscopy · MIT · PhD
Water absorption and moisture emission introduce severe spectral distortion
Strong optical absorption and additive emission noise from ambient water vapor or liquid water obstruct key spectral regions. These aqueous background signals attenuate light transmission, distort spectral baselines, and compromise quantitative analysis.
Considered and rejected
Considered and rejected: Mid-infrared (MIR) spectroscopy was rejected for in-field proximal NUE sensing due to requirement of sample preparation, spectral distortion, and strong masking by soil water.
Proximal sensing of soil properties for nitrogen use efficiency improvement · University College Dublin · PhD
Tried and failed
infrared spectroscopy detection using multi-pass absorption cell applied to trace volatile organic compound detection. Outcome: no signal. Reason: the analyte absorption peak overlapped with a dominant ambient water vapour absorption band
Nanoporous Silicon in Gas Preconcentration and Sensing · Cambridge · PhD
Tried and failed
thermal infrared imaging applied to in vivo gastrointestinal inflammation detection. Outcome: no signal. Reason: optical absorption and additive emission noise from luminal gases and water vapor obscured localized thermal features
Tried and failed
reflectance photoplethysmography at shortwave infrared wavelengths applied to optical haematocrit ratio estimation. Outcome: unstable. Reason: strong water absorption and small photodiode area caused severe optical attenuation and noisy ratios
Wearable multi-wavelength photoplethysmography and algorithms for continuous non-invasive monitoring of Dengue fever · Imperial · PhD
Tried and failed
transmission mode FTIR spectroscopy applied to aqueous chromatographic resin beads. Outcome: no signal. Reason: strong water absorption and large bead dimensions prevented optical transmission
Monitoring of biotherapeutic purification by vibrational spectroscopy · Imperial · Doctorate
Considered and rejected
Considered and rejected: Rejected water baseline subtraction during IR/Raman preprocessing because IR water baseline is overly sensitive to probe position and agitation speed, introducing spectral artifacts.
Development of In Situ Monitoring and Data-Driven Modeling for Complex Systems: Case Study on Simulant Mixtures of Nuclear Waste · Georgia Tech · PhD
Considered and rejected
Considered and rejected: Rejected using reconstituted actin in standard H2O for 2D-IR spectroscopy due to the overwhelming background water OH vibrational band in the amide I region, substituting D2O.
In-vitro active gels: quantifying actin network interactions and morphologies · UT Austin · PhD
Considered and rejected
Considered and rejected: Decided against quantitatively interpreting the broad bridge-bound CO infrared feature due to its excessive breadth and convolution from water vapor evacuating from the catalyst layer.
The Electrochemical Nature of Non-Faradaic Catalysis at Interfaces · MIT · PhD
Considered and rejected
Considered and rejected: Temperature measurements located in the gap areas between non-active and active chromium coatings were excluded/rejected from analysis due to infrared emission interference from water causing count discontinuities.
Inferencing Techniques for Enhanced Monitoring of Thermal-Fluid Systems · MIT · PhD
Inadequate spectral resolution or absent peak shifts prevent discrimination between structural states
Spectrometer configurations sometimes lack the spectral resolution required to separate narrow fingerprint modes or distinguish closely related polymer grades. In other instances, target physical transitions produce no measurable vibrational frequency shifts or infrared absorption at the monitored wavelengths.
Considered and rejected
Considered and rejected: Rejected Stokes-to-anti-Stokes intensity ratio Raman thermometry due to required doubling of spectral range (degrading resolution) and extremely weak anti-Stokes signal at ambient to moderate temperatures.
Understanding heat transport at interfaces for thermal management of electronics · MIT · PhD
Tried and failed
Raman spectroscopy for localized stress characterization applied to laser-micromachined silicon surfaces. Outcome: no signal. Reason: laser-induced surface modifications and shallow stress depths produced undetectable Raman frequency shifts
Ultrafast Laser Micromachining for Correction of Thin Optics for Next Generation X-ray Space Telescopes · MIT · PhD
Considered and rejected
Considered and rejected: Rejected relying solely on FTIR spectroscopy for identifying polyethylene waste types due to lack of distinct absorption differences at 4 cm-1 resolution; adopted DSC second-heating analysis instead.
Tried and failed
infrared center-frequency shift spectroscopy applied to detecting biomolecular condensate desolvation. Outcome: no signal. Reason: vibrational lineshapes showed no appreciable frequency shifts between dilute and condensate phases despite phase separation
Gotta keep ‘em separated : probing phase separation with infrared spectroscopy · UT Austin · PhD
Left open by the authors
Problems the authors named and did not get to.
Left open
Spectrally filter the Raman laser using Echelle gratings to rectify anomalous Raman scattering rates. Blocker: Requires optical lab hardware, a physical Raman laser system, and trapped ion apparatus.
Multi-tone Mølmer-Sørensen interaction outside of the Lamb-Dicke regime · Imperial · PhD
Left open
Improve Raman spectroscopy sensitivity and disc triggering to measure spectra of lubricant films thinner than 1.5 µm. Blocker: Requires a physical experimental elastohydrodynamic lubrication rig and Raman spectroscopy hardware setup
Effect of polymers on lubricant rheology in an elastohydrodynamic contact · Imperial · PhD
Left open
Perform high-resolution characterisation to identify unidentified Raman peaks at 1456 cm^-1 in RR2450 and 1468/1601 cm^-1 in Stellite 20. Blocker: Requires physical access to alloy samples and advanced characterisation / Raman spectroscopy laboratory equipment.
Sliding wear tests and numerical modelling of Co- and Fe- based alloys · Imperial · PhD
Left open
Synthesize bioorthogonal Raman probes functionalized with isotopes, azides, or triple bonds for intracellular Raman detection. Blocker: Requires a wet chemistry and cell culture lab to synthesize probes and perform intracellular Raman spectroscopy
Polypyrrole-coated gold nanoflowers as multifunctional nanoparticles for cancer theranostics · Imperial · PhD
Left open
Extend Loudon-Fleury Raman response calculations to incorporate crystalline topological defects in two- and three-dimensional quantum magnet models. Blocker: Lack of specified analytical models or tractable 2D/3D tensor network algorithms for defect-modulated Raman response
Dynamics and Transport in Strongly Correlated Quantum Magnets · Georgia Tech · PhD
Left open
Develop and evaluate multimodal optical sensing combining DRS with Raman spectroscopy, fluorescence spectroscopy, or hyperspectral DRS imaging. Blocker: Requires custom physical optical hardware, spectrometer instrumentation, and physical/biological tissue samples.
Sensing rectal cancer hypoxia for advanced prognostication and response monitoring · Imperial · PhD
Left open
Record simultaneous low- and high-dispersion Raman spectra to measure gas composition and temperature accounting for H2O and CO2 broadening. Blocker: Requires a physical experimental Raman spectroscopy lab apparatus and high-pressure gas setup
Thermometry in high pressure gases using spontaneous Raman scattering · UT Austin · PhD
Who has worked on this
Authors of the public theses cited on this page, most-cited first.
- James Beattie · Imperial · Doctorate · 2023
Monitoring of biotherapeutic purification by vibrational spectroscopy - Simon Dale Dryden · Imperial · PhD · 2022
Raman spectroscopy for point of care urinary tract infection diagnosis - Christina Evelina Buffo · Georgia Tech · PhD · 2025
Infrared Spectroscopy at Three and Six Microns of Water Ices Mixtures of Astrochemical Interest - Yun Ma · Imperial · PhD · 2023
Polypyrrole-coated gold nanoflowers as multifunctional nanoparticles for cancer theranostics - Richard Lobo · Imperial · Doctorate · 2023
Unraveling the fluorescence puzzle: examining the role of purification and passivation in carbon dots - Stefani Kocevska · Georgia Tech · PhD · 2022
Development of In Situ Monitoring and Data-Driven Modeling for Complex Systems: Case Study on Simulant Mixtures of Nuclear Waste - Jingzhe Li · Iowa State · PhD · 2022
Advanced applications of Raman spectroscopy and machine learning techniques - Hyun-Chae Loh · MIT · PhD · 2021
Time-Space-Resolved Raman Analysis of Structure-Property Relationships in Heterogeneous Structural Materials - Daniel Lewis Magley · MIT · PhD · 2026
Wireless Thermal Capsule Endoscopy: A Bowel Preparation Free, Sedation Free, Outpatient Alternative to Colonoscopy - Anthony Martin Toroitich · De Montfort University · PhD · 2026
RETROSPECTIVE DESCRIPTIVE STUDY ON POST-MARKET MEDICINE QUALITY-RELATED COMPLAINTS AND THE APPLICATION OF FIELD-BASED DETECTION OF POORQUALITY MEDICINES USING NEAR-INFRARED AND RAMAN SPECTROSCOPIC SCR - Sherif Shaheen · University College Dublin · PhD · 2026
Signature of Irish grass-fed beef - Authentication of the dietary background and geographical origin of Irish grass-fed beef using chromatographic and rapid spectroscopic techniques integrated with ch - Fletcher Edward · Imperial · PhD · 2025
Sensing rectal cancer hypoxia for advanced prognostication and response monitoring
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