F-19 NMR Spectroscopy

F-19 NMR provides highly sensitive, direct detection of fluorine atoms in organic and inorganic compounds.

With 100% natural abundance and 83% the sensitivity of proton NMR, F-19 NMR is an extremely powerful technique for characterizing fluorinated pharmaceuticals, agrochemicals, polymers, and specialty materials. Fluorine's wide chemical shift range (-300 to +300 ppm) provides excellent resolution for complex molecules.

Why F-19 NMR?

Exceptional NMR Properties

F-19 is one of the best nuclei for NMR spectroscopy:

  • 100% natural abundance - Only stable isotope of fluorine
  • High sensitivity - 83% relative to H-1 (nearly as sensitive as proton NMR!)
  • Spin 1/2 nucleus - Sharp, well-defined peaks (not quadrupolar)
  • Wide chemical shift range - ~600 ppm total range provides excellent dispersion
  • Minimal background - No fluorine in NMR tubes
  • Fast acquisition - Similar to H-1 NMR in terms of experiment time

What F-19 NMR Reveals

Structural Information

  • Number of fluorine environments - Each peak = unique F
  • Chemical environment - Aromatic vs aliphatic vs trifluoromethyl
  • Coupling patterns - F-F and F-H coupling reveals connectivity
  • Isomers - Distinguish positional isomers (ortho, meta, para)
  • Tautomers - Detect equilibrium between forms
  • Purity - Detect fluorinated impurities

Quantitative Information

  • Integration - Count fluorine atoms
  • Regioisomer ratios - Quantify isomeric mixtures
  • Polymer composition - Fluoropolymer analysis
  • Reaction monitoring - Track conversion and yield
  • Fluorine content - Measure %F in materials (ie. TFA impurity quantification)




F-19 Chemical Shift Ranges

Functional Group Chemical Shift Range (ppm) Example
CF₃ (aliphatic) -60 to -90 CF₃COOH (-76 ppm)
CF₃ (aromatic) -55 to -70 PhCF₃ (-63 ppm)
ArF (aromatic fluorine) -100 to -170 Fluorobenzene (-113 ppm)
CF₂ groups -80 to -140 CH₂CF₂CH₃ (-114 ppm)
C-F (aliphatic) -180 to -240 CH₃CH₂F (-213 ppm)
SF₅, SF₆ +40 to +90 SF₆ (+56 ppm)
Perfluorinated compounds -80 to -130 Teflon (-120 ppm)
F-C=O (acyl fluorides) +10 to +50 CF₃COF (+20 ppm)

Reference Standard: CFCl₃ (trichlorofluoromethane, Freon-11) is used as the reference at 0.0 ppm. Some spectra may also be referenced to C₆F₆ (hexafluorobenzene) at -164.9 ppm.

Applications of F-19 NMR

Pharmaceutical Applications

  • Drug development - ~20% of drugs contain fluorine
  • Fluorinated APIs - Structure verification
  • Metabolite identification - Track fluorinated metabolites
  • Formulation analysis - Fluorinated excipients
  • Purity assessment - Detect fluorinated impurities such as TFA
  • Positional isomers - ortho, meta, para-fluoro compounds

Common Fluorinated Drugs:

  • Fluoxetine (Prozac)
  • Atorvastatin (Lipitor)
  • Ciprofloxacin (Cipro)
  • 5-Fluorouracil (cancer treatment)

Materials & Polymers

  • Fluoropolymers - PTFE, PVDF, FEP analysis
  • Fluorinated surfactants - PFAS compounds
  • Fluoroelastomers - Viton, Kalrez
  • Coatings - Non-stick, hydrophobic surfaces
  • Refrigerants - CFCs, HFCs, HFOs

Agrochemicals & Specialty

  • Pesticides - Many contain CF₃ groups
  • Herbicides - Fluorinated active ingredients
  • Building blocks - Fluorinated synthons
  • Organofluorine chemistry - Method development

F-19 NMR vs H-1 NMR

Property F-19 H-1
Natural Abundance 100% 99.98%
Relative Sensitivity 83% 100% (reference)
Chemical Shift Range ~600 ppm (-300 to +300) ✓ ~15 ppm (0-15)
Coupling with H-1 Yes (JHF = 0-80 Hz) Yes (JHF = 0-80 Hz)
Background Signals None ✓ Some (grease, water, solvents)
Typical Experiment Time Similar to H-1 5-15 minutes

When to Use F-19 NMR

F-19 NMR is essential when:

  • Your compound contains fluorine atoms
  • You need to distinguish fluorine positional isomers
  • You're developing fluorinated pharmaceuticals
  • You're analyzing fluoropolymers or PFAS
  • You need high sensitivity for trace fluorinated impurities
  • You want to monitor reactions involving fluorinated reagents
  • You want to quantify fluorinated impurities such as TFA

Complementary to H-1 and C-13: Order F-19 NMR alongside H-1 and C-13 NMR for complete structural characterization of fluorinated compounds.

Sample Requirements

Sample Amount

  • Minimum: 1-5 mg (may require long run)
  • Recommended: 10-20 mg for best results

Solvent

  • Common solvents: CDCl₃, DMSO-d₆, acetone-d₆, D₂O
  • Avoid: Fluorinated solvents (will interfere)
  • Reference: Spectra is externally referenced to CFCl₃

Concentration

  • 5-15mg/ml typical
  • Lower concentrations acceptable due to high sensitivity

Turnaround Time & Pricing

Standard Turnaround: 2-3 business days (typically we only run F-19 in the mornings)

Factors affecting acquisition time:

  • Molecular weight and complexity
  • Desired signal-to-noise ratio
  • Number of scans required

Complexity:

For pricing information, please visit our Pricing page or contact us.

What You'll Receive

Standard Deliverables

  • F-19 NMR spectrum (H-1 Decoupled)
  • Peak list with chemical shifts (ppm)
  • Integration values
  • Coupling constants (JHF, JFF if applicable/wanted)
  • Raw data files (Bruker format)
  • PDF report

Optional Add-Ons

  • H-1 coupled F-19 - Let us know if you want to see H-F coupling

Need F-19 NMR Analysis?

Submit your fluorinated compounds for expert F-19 NMR spectroscopy

Submit a Sample Request a Quote

Phone: (858) 793-6057 | Email: NuMegaLab@NuMegaLabs.com

H-1 NMR

Proton NMR analysis

C-13 NMR

Carbon skeleton

P-31 NMR

Phosphorus analysis

Other Nuclei

Multinuclear NMR