dating at com - Carbon 14 dating calibration
A more recent innovation is the direct counting of c14 atoms by accelerator mass spectrometers (AMS).The sample is converted to graphite and mounted in an ion source from which it is sputtered and accelerated through a magnetic field. Since carbon is fundamental to life, occurring along with hydrogen in all organic compounds, the detection of such an isotope might form the basis for a method to establish the age of ancient materials.
Bases may be used to remove contaminating humic acids.
Some types of samples require more extensive pre-treatment than others, and these methods have evolved over the first 50 years of radiocarbon dating.
Any organic material that is available in sufficient quantity can be prepared for radiocarbon dating.
Modern AMS (accelerator mass spectroscopy) methods require tiny amounts, about 50 mg.
During the lifetime of an organism, the amount of c14 in the tissues remains at an equilibrium since the loss (through radioactive decay) is balanced by the gain (through uptake via photosynthesis or consumption of organically fixed carbon).