Isotope Dilution Analysis

Isotope dilution analysis (IDA) is used to quantitatively analyze and accurately determine the concentration of specific substances in a sample. It involves adding a known amount of an isotopically labeled substance (the "spike") to a sample and then measuring the ratio of the labeled substance to the unlabeled substance.

Alfa Chemistry offers specialized IDA services that utilize the addition of isotope-labeled substances for accurate quantitative analysis. We follow stringent quality control and assurance procedures to ensure data accuracy and reliability. Whether you are looking for academic research, environmental monitoring, food safety, or drug discovery, we can provide you with customized solutions.

Principle of IDA

Principle of IDA

The principle of IDA analysis relies on the fact that the spike and the target substance have the same chemical and physical properties, but they have different isotopic compositions. Typically, the spike contains heavier stable isotopes of the same element as the target substance. For example, if the target substance is element X, the spike will contain the heavier X isotope.

The key concept of IDA is that the addition of a spike has a diluting effect on the target substance. Since the spiked concentration is known, the dilution effect can be mathematically accounted for during the calculation of the target substance concentration. This dilution effect helps eliminate potential errors due to losses, incomplete recoveries, or variations in sample preparation and analysis.

Alfa Chemistry's Workflow

1. Sample preparation: Extraction, purification, pretreatment and appropriate dilution of the sample.

2. Spiking: A known amount of isotope labeling substance is added to the sample.

3. Mixing: The sample and the spiked material are mixed thoroughly to ensure that the labeled substance is evenly distributed in the sample.

4. Analysis: The mixture is then analyzed using appropriate analytical techniques such as gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and atomic absorption apectrometry (AAS) depending on the nature of the target substance.

5. Measurement of isotope ratios: The isotope ratio of labeled to unlabeled substances is determined using the analytical technique of choice. The ratio provides information about the concentration of the target substance in the original sample.

6. Concentration Calculation: Calculates the concentration of the target substance in the sample based on the known spiked amount and the measured isotope ratio.

Species-specific isotope dilution analysis using GC/ICP-ToF-MSFig 1. Species-specific isotope dilution analysis using GC/ICP-ToF-MS[1].

Below are our common tracers for isotope dilution.

3H12.5 years
14C5730 years
32P14.3 days
35S87.1 days
45Ca152 days
55Fe2.91 years
60Co5.3 years
131I8 days

Alfa Chemistry's IDA Service Items

ItemsMain content
Environmental contaminant analysisIDA is used to quantify contaminants such as heavy metals, pesticides, PCBs (polychlorinated biphenyls) and dioxins in environmental samples such as soil, water, sediment and biota.
Food origin certificationIDA can be used to verify the authenticity and origin of food products by quantifying specific markers or isotope ratios.
Drug metabolism studiesIDA is used to measure drug metabolites in biological samples to understand drug metabolism and elimination in the body.
Pharmacokinetic studiesIDA helps to determine the concentration of a drug in biological fluids to characterize the absorption, distribution, metabolism and excretion of the drug.
Impurity quantificationIDA assists in quantifying impurities and degradation products in drug formulations to ensure product quality and safety.
Radioactive substance analysisIDA is used to analyze radioactive materials, such as uranium or plutonium isotopees, to determine their origin and history, contributing to nuclear forensic investigations.
Metabolomics studiesIDA assists in the quantification of metabolites in biological samples, providing insights into metabolic pathways and disease biomarkers.

Please contact us for more detailed information about our isotope dilution analysis services, including pricing, sample requirements, and analysis cycle time. We look forward to providing you with quality isotope dilution analysis services.


  1. Faßbender S, et al. "Species-specific isotope dilution analysis of monomethylmercury in sediment using GC/ICP-ToF-MS and comparison with ICP-Q-MS and ICP-SF-MS." Analytical and Bioanalytical Chemistry. 2021, 413, 5279-5289.
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