Innovation and Partnerships Office

Highly Sensitive Detector for Radiotracer Chromatography IB-2765


  • Analytical radiotracer high performance liquid chromatography (HPLC)
  • Research of metabolic pathways for biofuels, drug development and medical diagnostics


  • One hundred times more sensitive than existing radiotracer HPLC
  • Can be manufactured with existing hardware


Scientists at Berkeley Lab have developed an apparatus that increases, by a factor of 100, the sensitivity of radiotracer high performance liquid chromatography (HPLC). The apparatus detects concentrations of radiolabeled substances that typically fall below the detection threshold of existing instrumentation. The invention does this by providing greater solid angle coverage and prolonging the measurement time to increase the number of disintegrations recorded.

The most sensitive existing radiotracer HPLC works by directing the outflow of the column through a tube that is coiled around a radiation detector. The Berkeley Lab invention instead passes the outflow through either a longer coiled tube or additional separation columns that run between the parallel-planes of a positron emission tomography (PET) camera. As each separated analyte passes between the camera planes over several minutes, its emissions are continuously detected and effectively registered as a moving peak. Computer software then merges the data from all of the time points to determine the speed and area of each peak.

Berkeley Lab scientists built a bench scale prototype of the new apparatus to compare with a conventional radiation detector (a small scintillator coupled to a photodiode). The new apparatus produced peaks that were similar in shape to those of the conventional detector, but with a signal-to-noise ratio that was 10 times higher. Statistically, achieving the same signal-to-noise ratio using the conventional detector would require 100 times more data.

Existing analytic radiotracer HPLC is limited in its ability to detect substances at very low concentrations, such as short-lived intermediate metabolites. Tests demonstrated that the Berkeley Lab device could measure tracer activities as low as 4 nCi, with a signal-to-noise ratio of 27:1. Because this new technology can detect substances at concentrations too low to be detected with conventional systems, it can provide useful analyses of metabolic pathways researched in the development of biofuels, medications, and diagnostic tests.

STATUS: Issued U. S. Patent Application #9170242. Available for licensing or collaborative research.

DEVELOPMENT STAGE: Bench scale prototype developed.