Two types are commonly used: fixed tungsten or silver electrodes; or disk and rod graphite electrodes. Both operate with an oil sample in the gap between them. Spectrometers use light wavelengths to investigate the chemical composition of a sample. Strictly speaking, a spectrometer is any instrument used to view and analyze a range (or a spectrum) of a given characteristic for a substance (for example, a range of mass-to-charge values as in mass spectrometry), or a range of wavelengths as in absorption spectrometry like nuclear magnetic. in interfe Spectral analysis is a method that uses the spectrum emitted by elements or compounds for analysis.