31P NMR
Definition
Phosphorus-31 nuclear magnetic resonance spectroscopy, used to confirm the presence of phosphorus-containing OP nerve agents and their degradation products. Diagnostic: chemical shift (sarin ~+30 ppm; VX ~+35 ppm) and P-F/P-N coupling constants.
- Full name
- Phosphorus-31 nuclear magnetic resonance spectroscopy
- Use
- Confirms OP nerve agents and degradation products
- Diagnostic signal
- Chemical shift and P-F/P-N coupling constants
- Example shifts
- Sarin ~+30 ppm; VX ~+35 ppm
Common questions
Why is 31P NMR particularly well suited to nerve agent analysis?+
Nerve agents are organophosphates with a phosphorus atom central to their toxicity, and phosphorus-31 is NMR-active, so the technique probes the chemical environment around that specific atom, giving a distinctive spectroscopic fingerprint for the agent class.
How does 31P NMR complement mass spectrometry in agent identification?+
NMR provides structural and bonding detail, such as chemical shift and coupling patterns, that can distinguish isomers or confirm functional groups, while mass spectrometry mainly gives molecular mass and fragmentation, so combining both increases confidence in the identification.
Related terms
- AChE (Acetylcholinesterase)
- The enzyme that terminates cholinergic nerve impulses by hydrolysing acetylcholine. Irreversibly phosphorylated at Ser203 by OP nerve agents, causing accumulation of acetylcholine...
- IMPA (Isopropyl Methylphosphonic Acid)
- The primary hydrolysis product of sarin (GB). Detected in urine of sarin-exposed individuals and in environmental matrices by GC-MS and LC-MS/MS. The...
- Novichok (A-Series)
- A class of Soviet-era phosphoramidate nerve agents (A-230, A-232, A-234) from the Foliant programme. Reported to be 5-10x more toxic than VX....
- OCAD (OPCW Central Analytical Database)
- The OPCW's reference library of confirmed GC-MS and NMR spectra for all scheduled chemicals and their degradation products, used by Designated Laboratories...
- OPCW Designated Laboratory
- A laboratory authorised by the Organisation for the Prohibition of Chemical Weapons to conduct official CWC verification analysis. Must pass biennial proficiency...
- Sarin (GB)
- Isopropyl methylphosphonofluoridate, a G-series nerve agent. Highly volatile, AChE inhibitor. LCt50 ~35 mg.min/m3 by inhalation. Key degradation products: IMPA (isopropyl methylphosphonic acid)...
- Schedule 1 (CWC)
- The list of chemicals with little or no commercial use outside chemical weapons under the Chemical Weapons Convention. Includes all nerve agents...
- Sulphur Mustard (HD)
- Bis(2-chloroethyl) sulphide. The prototype vesicant (blister agent). Alkylates DNA and proteins via an ethylene sulfonium ion intermediate. First used at Ypres (1917)....
- VX
- O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate. A V-series nerve agent. Very low volatility, extreme skin-penetration toxicity. Developed by ICI (UK) in the 1950s. Used in...