Carbon 12 dating accuracy
AMS technology has allowed us to date very small samples (such as seeds) that were previously undatable.
Since there are practical limits to the age range of the method, most samples must be younger than 50,000 years and older than 100 years.
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.
The sample must be destroyed in order to measure its c14 content.
Acids may be used to eliminate contaminating carbonates.This is the clock that permits levels of c14 in organic archaeological, geological, and paleontological samples to be converted into an estimate of time.The measurement of the rate of radioactive decay is known as its half-life, the time it takes for half of a sample to decay.These so-called "solid-carbon" dates were soon found to yield ages somewhat younger than expected, and there were many other technical problems associated with sample preparation and the operation of the counters.Gas proportional counters soon replaced the solid-carbon method in all laboratories, with the samples being converted to gases such as carbon dioxide, carbon disulfide, methane, or acetylene.