Stable isotope-labeled standards expertise

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Shimadzu Chemistry & Diagnostics has been involved in the R&D of SIL compounds for over 20 years and offers expertise and know-how in the synthesis of stable isotope-labeled compounds such as SIL analogues, building blocks, metabolites, reference standards.
Thanks to our wide catalog of products or our custom synthesis service, we provide the ideal compound you need to allow accurate results and improve your LC-MS/MS analytical method.
Our analytical department analyze all our compounds with high analytical instruments, such as NMR, HPLC, GC, MS to ensure a comprehensive quality to our customers, and deliver a detailed certificate of analysis. To provide the quality of our products, we ensures and controls the whole process: from the R&D and the manufacturing, to the delivery.

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Use Cases of Our Products

Category Keywords
Stable Isotope Standards Stable isotope labeled analytical standards, Internal standard, Deuterium labeled standards, Carbon 13
Reference Standards Pesticides references, Pharmaceutical reference standard, Pharmaceutical analytical testing, Method validation
Therapeutic Drug Monitoring (TDM) TDM products

What are Isotopes?

Isotopes: Atoms with the same atomic number (number of protons), but with different mass numbers (number of neutrons).

  Hydrogen (H) Deuterium (2H or D) Tritium (3H or T)
Structure

structure of hydrogen

structure of Deuterium

structure of Tritium
    proton
Mass Number 1 2 3
Radioactivity No No
(stable isotope)		 Yes
(radioactive isotope)
Natural Abundance 99.985% 0.015% Trace

 

Water on Earth contains an average of about 150 ppm (150 µL per liter of water) deuterium (D2O).

Element Symbol H C N O
Mass / Natural Abundance (%) 1.0078
2.0141		 99.9885
0.0115		 12.0000
13.0034		 98.93
1.07		 14.0031
15.0001		 99.632
0.368		 15.9949
16.9991
17.9991		 99.757
0.038
0.205
Element Symbol S Cl Br  
Mass / Natural Abundance (%) 31.9721
32.9715
33.9679
35.9671		 94.93
0.76
4.29
0.02		 34.9867
36.9659		 75.78
24.22		 78.9183
80.9163		 50.69
49.31		  

Tip:

  • Isotope comes from Greek «Isos» which means "same", and «topos» meaning "location".

Stable Isotope Labeled (SIL) Compounds

Ex: Levetiracetam

Levetiracetam → [2H6]-Levetiracetam (Levetiracetam-d6)

  • levetiracetam structure

    Levetiracetam

    Molecular Formula: C8H14N2O2
    Monoisotopic Mass (M): 170.1055
    Detected Ion [M+H]+: 171.1

  • levetiracetam-d6 structure

    [²H₆]-Levetiracetam (Levetiracetam-d6)

    Molecular Formula: C8H8D6N2O2
    Monoisotopic Mass (M): 176.1432
    Detected Ion [M+H]+: 177.1

  • Mass Spectrum

    Mass Spectrum

  • mass chromatogram

    Mass Chromatogram

Characteristics of SIL Compounds:

  • Almost physicochemically identical to the original compound.
  • Pretreatment recovery rate is almost the same.
  • HPLC retention time is almost the same.
  • MS ionization efficiency (matrix effects) is almost the same.

Stable Isotope Labeling (SIL)

  • First Generation: Deuterium (2H or D) Labeling

    • Relatively easy to synthesize and inexpensive.
    • Deuterium desorption (replaced by hydrogen atoms).
    • Retention time shift due to the isotope effect.
    • But isotopic purity may be lower and can present lower stability.

  • Second Generation: 13C / 15N / 18O Labeling

    • Chemical stability can be improved by labeling in areas not prone to external effects.
    • High purity.
    • Complex synthesis results in high cost.

Characteristics of Good SIL Compounds:

  • High purity: Contains no unlabeled compounds.
  • Number of labels: A number that avoids overlap with unlabeled compounds.
  • Label position: Applied in stable locations. Applied to product ions.
  • Label type: 13C used.
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