WHAT IS RADIOCHROMATOGRAPHY?

Chromatography is a laboratory method performed to separate the different components of a mixture. The mixture is dissolved in a fluid called the mobile phase. The mobile phase carries the mixture through a column which is the stationary phase. The various compounds of the mixture travel at different speeds through the column causing them to separate.

In order to measure the separation of the mixture the compounds must be detectable in some way. There is no universal detector that can monitor all compounds, and therefore different types of HPLC detectors must be used depending on the properties of the substances to be separated. UV detectors are often used, as many substances typically separated in HPLC absorb light in the UV range of light. Other detectors such as, refractive index, light scattering, fluorescence, conductivity, and more, are also used in HPLC. The intensity of the signal measured will be represented in the graph called chromatogram. Assuming complete separation, each compound will appear in the chromatogram as a peak. The time of appearance identifies the compound, and the area of the peak quantifies it. In the case of Radio-HPLC (or radio chromatography), the substances to be separated are radioactive because they have been labeled using a radioactive isotope, such as 125I, 14C or 3H.

APPLICATIONS OF RADIO-HPLC

Radio-HPLC has numerous applications in research, diagnostics, and quality control. Some of the most common and important applications are:

Pharmaceutical Analysis: Radio-HPLC is a key technology for the separation and quantitation of radiolabeled drugs and putative metabolites in drug development.

Environmental Analysis: A wide variety of contaminants from sources such as industrial waste, landfill sites, pesticides and pharmaceutical drugs can make their way into the environment. The challenging identification of these contaminants require a highly sensitive detector to be able to detect the lowest concentrations of sample.

Development and QC of Radio chemicals: Radiochemicals are only as good as the care taken in each preparation step and strict regulations must be met during production. Radiochemical purity analysis using Radio HPLC is often required to verify the quality of the produced radiochemicals.

QC of Radiolabeled Antibodies and Proteins: Radiochemical identity and purity analysis of radiolabeled antibodies and proteins using Radio-HPLC is a simple and reliable method to ensure that only the radiolabeled antibody or protein is present in the quality control sample.