Final answer:
Quantitative spectroscopy in chemistry involves determining the quantity of a substance or particles in a sample by analyzing the interaction of light with matter. Various techniques and instruments, such as mass spectrometry, are used for this purpose.
Step-by-step explanation:
Quantitative spectroscopy is a branch of chemistry that tries to determine the quantity of a substance or the amount of particles in a sample. It involves using various techniques and instruments to analyze the interaction of light with matter and measure the amount of light absorbed or emitted by a substance. For example, mass spectrometry is a quantitative spectroscopy method used to determine the occurrence and natural abundances of isotopes in a sample.