What is mass spectra primarily used to analyze?

Mass spectra are primarily used to analyze patterns of molecular fragmentation. This technique involves measuring the mass-to-charge ratio of ions, which provides insight into the composition and structure of chemical compounds. When molecules are ionized, they can fragment into smaller pieces, and the resulting mass spectrum reveals these fragmentation patterns.

By examining the specific masses and intensities of the resulting ions, analysts can determine the molecular weight of the original compound and infer structural information from the fragmentation pattern. This is especially valuable in forensic science for identifying unknown substances, analyzing drugs, or determining the presence of toxins in biological samples.

The other options do not align closely with the primary function of mass spectrometry. While mass spectrometry may indirectly support analyses related to elements in a fire, biological evidence, or fluid consistency, these are not the primary use cases of mass spectra. Instead, those scenarios typically involve other analytical techniques or methodologies tailored to the specific types of evidence being examined.