The smallest amount of a pure material that can be analyzed by spectroscopy is?

In spectroscopy, the smallest amount of a pure material that can be effectively analyzed is determined by the sensitivity of the spectroscopic method being used and the specific properties of the material in question. In many cases, spectroscopic techniques can analyze samples in very small quantities, often much less than a gram.

The correct answer, which indicates that 1 milligram is typically sufficient for many spectroscopic analyses, emphasizes that advanced spectroscopic methods, such as mass spectrometry or UV-Vis spectroscopy, can detect and analyze analytes at very low concentrations. Techniques like these can often work with microgram or even nanogram quantities, depending on the sensitivity and calibration of the equipment.

Therefore, while larger quantities can certainly be analyzed, the progression of technology in spectroscopy means that even amounts as small as 1 milligram can provide sufficient data for analysis in many cases. The other options presented suggest larger minimum amounts, which do not align with the capabilities of modern spectroscopic techniques.