C-13 NMR Spectroscopy Testing Services

C-13 NMR reveals the complete carbon skeleton of organic molecules, providing essential complementary information to H-1 NMR.

C-13 NMR (Carbon-13 NMR or ¹³C NMR) is indispensable for complete structural characterization. While H-1 NMR shows hydrogen environments, C-13 NMR reveals the carbon framework, identifies quaternary carbons, and provides critical data for structure elucidation and verification.

What is C-13 NMR Spectroscopy?

C-13 NMR (Carbon-13 Nuclear Magnetic Resonance) spectroscopy detects the ¹³C isotope of carbon (natural abundance ~1.1%). It provides detailed information about:

Carbon functional groups - carbon framework of your molecule
Quaternary carbons - Carbons with no attached hydrogens
Carbonyl carbons - C=O groups (aldehydes, ketones, esters, amides)
Aromatic vs aliphatic - Distinguishes sp², sp³, sp carbons

Carbon types - CH₃, CH₂, CH, or quaternary C
Functional groups - Carbonyls, nitriles, alkenes, aromatics
Molecular symmetry - Equivalent carbons appear as one signal
Structure confirmation - Verify proposed molecular structures

Why C-13 NMR is Essential for Complete Characterization

Information You CANNOT Get from H-1 NMR Alone

H-1 NMR only detects hydrogens, leaving critical structural questions unanswered:

Quaternary carbons - Carbons with no H's attached are invisible in H-1 NMR
Carbonyl positions - C=O carbons have no hydrogens
Aromatic substitution patterns - Where substituents attach to aromatic rings
Carbon count - Total number and types of carbons in the molecule
Molecular symmetry - How many unique carbon environments exist

Bottom line: C-13 NMR provides the carbon skeleton that H-1 NMR cannot reveal.

C-13 NMR vs H-1 NMR: Understanding the Differences

Characteristic	H-1 NMR	C-13 NMR
What it detects	Hydrogen atoms (¹H)	Carbon atoms (¹³C)
Natural abundance	99.98%	~1.1%
Sensitivity	Very high	Lower (needs more sample or time)
Typical turnaround	24 hours	2-5 business days
Shows quaternary carbons?	No	Yes ✓
Shows carbonyl carbons?	No	Yes ✓
Chemical shift range	~0-15 ppm	~0-220 ppm (wider range = better resolution)
Sample amount needed	1-10 mg (may require long or overnight run)	20-100 mg (more for best results)

Key Takeaway: H-1 and C-13 NMR are complementary. Together, they provide complete structural information.

Common Applications of C-13 NMR

Structure Elucidation

Determine the complete carbon framework of unknown compounds or verify proposed structures. Essential for natural product chemistry and synthetic chemistry.

Quaternary Carbon Identification

Locate carbons with no attached hydrogens - critical for identifying substitution patterns, branching points, and aromatic substitution.

Carbonyl Carbon Detection

Identify and distinguish C=O groups in ketones, aldehydes, carboxylic acids, esters, and amides based on chemical shift (~160-220 ppm).

Aromatic & Aliphatic Regions

Distinguish aromatic (sp²) from aliphatic (sp³) carbons and identify alkenes, alkynes, and conjugated systems.

Natural Product Structure

Essential for natural product characterization - terpenes, alkaloids, flavonoids, and other complex molecules require C-13 NMR.

Polymer Characterization

Analyze polymer composition, sequence, and tacticity - determine monomer ratios and repeating units.

DEPT and APT: Enhanced C-13 Analysis

We generally default to DEPTQ (Distortionless Enhancement by Polarization Transfer including the detection of Quaternary nuclei) but can run normal DEPT or APT (Attached Proton Test) experiments to distinguish carbon types if requested:

What DEPT/APT Shows

CH₃ groups - Methyl carbons (positive)
CH₂ groups - Methylene carbons (negative in DEPT)
CH groups - Methine carbons (positive)
Quaternary C - No signal (identifies C with no H's) unless running DEPTQ

Why this matters: Knowing whether a carbon is CH₃, CH₂, CH, or quaternary dramatically speeds up structure determination and eliminates ambiguity.

Typical C-13 Chemical Shift Ranges

Carbon Type	Chemical Shift Range (ppm)	Examples
Alkyl (sp³)	0-50 ppm	CH₃, CH₂, CH groups in alkanes
Alkenes (sp²)	100-150 ppm	C=C double bonds
Aromatics (sp²)	110-160 ppm	Benzene rings, heteroaromatics
Alkynes (sp)	65-90 ppm	C≡C triple bonds
Carbonyls	160-220 ppm	C=O in ketones, aldehydes, acids, esters, amides
Nitriles	115-125 ppm	C≡N groups

Sample Requirements for C-13 NMR

Sample Amount

Minimum: 1-10 mg (may require long or overnight run)
Recommended: 20-100 mg for best results
Why more is needed: C-13 is only 1.1% naturally abundant, so requires more sample than H-1 NMR
Contact us if you have limited material

Sample Preparation

Solvent: Deuterated solvents (CDCl₃, DMSO-d₆, D₂O, CD₃OD, etc.)
Concentration: 1-50+ mg/mL (higher = faster acquisition)
Purity: Higher purity gives cleaner spectra
Volume: 0.5-0.7 mL in standard 5mm 7" NMR tube

Turnaround Time & Pricing

Standard Turnaround: 2-5 business days

Rush Service: Contact us for expedited analysis

Factors affecting acquisition time:

Sample concentration (higher = faster)
Molecular weight and complexity
Desired signal-to-noise ratio
Number of scans required

For pricing information, please visit our Pricing page or contact us. Pricing depends on sample complexity and turnaround requirements.

What You'll Receive

Standard Deliverables

spectrum (PDF)
Raw data files (upon request)
Peak picking
Acquisition parameters (upon request)

Optional Add-Ons

Peak assignment - spectral interpretation
2D NMR - HSQC, HMBC for complete assignment
Consultation - Discuss results with our chemists

Why Choose NuMega for C-13 NMR?

Expert Analysis

Our analytical chemists have decades of experience interpreting C-13 NMR spectra and solving structural problems

High-Field NMR

500 MHz Bruker NMR provides excellent resolution and sensitivity for challenging samples

Complete Service

Fast turnaround time, no extra fees for FID or processed data.

Ready to Determine Your Carbon Skeleton?

Submit your samples for C-13 NMR analysis

Submit a Sample Request a Quote

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