Final answer:
Quantitative analysis is performed using mass spectrometry, a technique where charged particles are separated by their mass-to-charge ratio and detected to determine the composition of a sample. The correct option is a).
Step-by-step explanation:
Quantitative analysis in chemistry involves determining the quantity or concentration of a substance in a sample. Two common approaches to performing quantitative analysis are mass spectrometry (MS) and gravimetric analysis. MS is a technique in which a sample is vaporized and charged particles (cations) are separated based on their mass-to-charge ratio using magnetic or electric fields. The process results in a mass spectrum, where the heights of the peaks represent the relative quantity of each ion. This detection and identification strategy is essential in various fields, such as environmental science and medicine.
Gravimetric analysis, on the other hand, is an older but still relevant method where mass measurements are used to calculate the concentration of an analyte. This process involves changing the physical state of the substance, thereby separating it from the sample, and basing the quantification on stoichiometry. While gravimetric analysis provided foundational techniques for chemical quantification, mass spectrometry has evolved to become a highly sensitive and powerful tool that can analyze complex mixtures and even facilitate protein analysis.