One limitation of Accelerator Mass Spectrometry (AMS) is its inability to provide structural identification of analytes. AMS can quantify radio-labeled analytes, but it cannot identify them. This limitation is not critical when the labeled compounds are well-characterized prior to AMS analysis. However, analyte identity is important in other experiments, such as when a compound is metabolized and the structures of its metabolites are not known.
Recognizing the need of the biomedical research community to obtain both types of data, the bioAMS facility integrates liquid-sample AMS capabilities with molecular mass spectrometry to simultaneously identify and quantify analytes labeled with carbon-14, in real time, from a single sample. This approach eliminates the need to characterize samples prior to AMS analysis.
Researchers at the bioAMS facility use this combined capability, known as Parallel Accelerator Molecular Mass Spectrometry (PAMMS), to provide measurements for studies that require metabolite separations using HPLC, DNA-adduct measurements, and quantification of drug incorporation into single cells. It enables accurate mass analyses for a variety of analytical applications, including metabolite profiling, identification, characterization, and quantification of both small and macromolecules with mass-to-charge ratios ranging from approximately 50–20,000.
How it works
PAMMS integrates the BioAMS instrument with a quadrupole-time-of-flight mass spectrometer. The HPLC instrument chromatographically separates the compounds in liquid samples, and the eluent is split into two sample streams. One stream is fed directly onto a moving nickel wire, where it is dried, converted to carbon dioxide, and directly fed into the AMS instrument’s ion source. The outcome of that analysis is quantitative data, measuring the ratio of a radioisotope to its stable form by counting individual radioisotopes.
The second stream is fed into the mass spectrometer, which sorts ions according to their mass-to-charge ratio and calculates their exact molecular weight. This process enables identification of unknown compounds by their molecular weight, providing the structural data needed to identify unknown samples. To learn more about how scientists have used the PAMMS capability in their research, browse our highlighted publications about bioAMS instrumentation and technology.
