Compound-specific isotope analysis (CSIA) is a high-resolution stable isotope analysis method used to measure the isotopic composition of individual organic compound molecules, such as carbon (C), nitrogen (N), oxygen (O), and hydrogen (H). CSIA usually involves analyzing stable isotopes of elements such as carbon (13C/12C), nitrogen (15N/14N), oxygen (18O/16O), and hydrogen (2H/1H). This technology has been widely used in environmental science, geochemistry, ecology, food traceability, forensics, and other fields.
Alfa Chemistry relies on a complete technical platform and a professional R&D team with global experimental analysis capabilities to provide you with compound-specific isotope analysis (C, N, O and H). We are committed to providing customers with accurate and fast analysis results and solving any research problems encountered by customers.
Compound Specific Isotope Analysis (CSIA)
| Project | Bulk isotope analysis | Compound-specific isotope analysis |
|---|
| Analysis object | Whole sample (such as total organic carbon) | Single compound (e.g. specific fatty acid) |
| Information accuracy | Low | High |
| Application depth | Rough determination of origin | Precise tracking of origin and transformation process |
Analyzable Elements
| Elements | Main representative compound types | δ Delta Notation |
|---|
| Carbon (C) | Organic acids, fatty acids, carbohydrates | δ13N |
| Nitrogen (N) | Amino acids, amines, nitrogen-containing heterocycles | δ15N |
| Oxygen (O) | Alcohols, carboxylic acids, sugars, water | δ18O |
| Hydrogen (H) | Fatty acids, alkanes, alcohols | δD (or δ2H) |
Analysis Methods and Instrument Principles
- GC-C-IRMS (gas chromatography-combustion-stable isotope mass spectrometry), used to analyze δ13N, δ15N.
- GC-Pyrolysis-IRMS (gas chromatography-pyrolysis-stable isotope mass spectrometry), used to analyze δ2H, δ18O.
Case Study
Example 1: Tracking the degradation path of oil pollution
| Compounds | δ13N Original value | δ13N after degradation | Explanation |
|---|
| n-hexadecane | -30.5‰ | -27.0‰ | Enrichment effect, indicating that degradation has occurred |
| aromatic hydrocarbons | -27.2‰ | -27.1‰ | Basically no change, no degradation |
Example 2: Amino Acid δ15N Trophic Level Analysis
| Amino Acids | δ15N value (herbivores) | δ15N value (carnivores) |
|---|
| Glutamic Acid | 8.0‰ | 13.0‰ |
| Phenylalanine | 4.5‰ | 4.7‰ |
| Difference | 3.5‰ | 8.3‰ → To calculate trophic levels |
Main Application Areas of Compound-specific Isotope Analysis
Environmental Science and Pollution Tracking
Compound-specific isotope analysis can be used to identify the source of pollutants (such as petroleum hydrocarbons, pesticides, and nitrates) and monitor the degradation pathways. For example, after an oil spill, analyzing the δ13N of a single alkane can determine its degree of biodegradation.
Ecology and Nutritional Ecology
Compound-specific isotope analysis can be used to analyze the precise trophic level of specific amino acids in animal tissues. For example, analyzing the isotopic information of fatty acids can determine the source of food (such as ocean/land).
Food Authenticity and Traceability
Compound-specific isotope analysis can be used to analyze the isotopic composition of specific ingredients in honey, alcohol, and vanilla to identify the origin or whether it is adulterated. For example, distinguish natural vanillin from synthetic vanillin.
Forensic Medicine and Anthropology
Compound-specific isotope analysis can assist in inferring eating habits and geographical origins by analyzing the isotopic levels of amino acids in hair or bones.
Geochemistry and Paleoenvironmental Reconstruction
Analysis of isotope levels of individual lipid compounds (such as n-alkanes) in sediments. Compound-specific isotope analysis is widely used to reconstruct paleoclimate and paleovegetation.
Advantages
- High resolution, capable of analyzing individual compounds.
- Strong traceability, capable of identifying different sources and transformation pathways.
- Often used in complex systems (such as environmental samples).
The advantage of compound-specific isotope analysis is that it can provide more detailed information than traditional chemical analysis, especially at the molecular level, which helps to reveal complex ecosystems and their interactions. It is also widely used in many fields such as environmental monitoring, forensic science, archaeology and food origin identification.
Alfa Chemistry is always happy to assist you set up a follow-up mechanism and interpreting results, particularly if they are unexpected.
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