around 50,000 years Theoretically we can report dates as young as a single year, but the margin for error may be greater than the date reported. On the other hand, if the sample is too old, not enough C-14 may remain for an accurate measurement. This means that the upper limit of C-14 dating is currently around 50,000 years ago.
Which material requires the smallest amount for 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. AMS technology has allowed us to date very small