Radio carbon dating chemistry
Burning the samples to convert them into graphite, however, also introduces other elements into the sample like nitrogen 14.When the samples have finally been converted into few milligrams of graphite, they are pressed on to a metal disc.There are two techniques in measuring radiocarbon in samples—through radiometric dating and by Accelerator Mass Spectrometry (AMS).The two techniques are used primarily in determining carbon 14 content of archaeological artifacts and geological samples.At this stage, other negatively charged atoms are unstable and cannot reach the detector.
This is done by conversion to carbon dioxide with subsequent graphitization in the presence of a metal catalyst.
An accelerator mass spectrometer, although a powerful tool, is also a costly one.
Establishing and maintaining an accelerator mass spectrometer costs millions of dollars.
Accelerator mass spectrometers need only as little as 20 milligrams and as high as 500 milligrams for certain samples whereas conventional methods need at least 10 grams in samples like wood and charcoal and as much as 100 grams in bones and sediments.
Accelerator mass spectrometers typically need sample sizes lesser than conventional methods by a factor of 1,000. Hence, because of its ability to analyze samples even in minute amounts, accelerator mass spectrometry is the method of choice for archaeologists with small artifacts and those who cannot destroy very expensive or rare materials.