Method for quantitative analysis of small samples of various compounds which has high accuracy. It involves passing the light refracted from a sample through a prism or diffraction grating that spreads out the wavelengths of trace elements into a spectrum. This enables the identification of different trace elements and depends on the fact that light emitted by any element on volatilization shows a characteristic pattern when split by a prism into its spectrum. The elements present can be measured by the intensity of the lines in comparison with control spectra of known composition produced under the same conditions. A small sample can be used, less than 10 milligrams, making the method particularly suitable for archaeological material. The method has been used especially for metal analysis, giving useful information on technology and sources of the raw materials, and also for glass, faience, pottery, and obsidian.