The combination of LC-ARC with radioactivity detection and mass spectrometry has great potential as a powerful tool for improving the sensitivity of radioisotope measurement in metabolite identification studies during drug discovery and development.
Used in conjunction with a conventional radio LC detector, LC-ARC (Liquid Chromatography - Accurate Radio-isotope Counting) employs StopFlow technology to increase sensitivity by 20 times or more, reliably detecting 10-20dpm peaks of 14C or 3H for complex matrices such as animal, plant and soil samples.
It is programmed to stop the flow at set intervals to count a pre-defined peak, or to count when a peak is detected, a one-step process that avoids the sequence of time-consuming and hazardous procedures necessary for off-line liquid scintillation counting.
Radioisotopes are used by scientists in many research areas such as metabolism. Flow-through radioactivity detectors have been used in radio-LC for radioactive peak detection. The current detection technology in radio-LC can only detect down to 200 ~ 500 DPM with a liquid cell or 500 ~ 1000 DPM with a solid cell, depending on the hardware and software used.
In order to detect/quantitate low level radioactivity (e.g. 10 DPM), it is a common practice to collect fractions and count them off-line to lengthen the counting time for each fraction. This practice is very time-consuming, expensive and may loss volatile metabolites thus resulting in inaccurate results. There is a great need to have a on-line sensitive system in radio-LC.
As well as achieving lower background, higher sensitivity and sharper peak resolution, LC-ARC has other benefits such as accurate quantification of volatile metabolites/degradates, accurate column recovery, advanced data evaluation and reporting without any manual operations.
Where necessary, the outgoing flow from the HPLC column can be split between the radio detector and a mass spectrometer to allow simultaneous profiling and identification of radiolabelled compounds. The whole process can be set up to run overnight, freeing laboratory manpower for other, more demanding tasks.
LC-ARC is available in Europe from LabLogic Systems, which has already supplied the product to four companies in the UK and Denmark.