A copper wire is cleaned and heated in a Bunsen burner flame to form a coating of copper(II) oxide. It is then dipped in the sample to be tested and once again heated in a flame. A positive test is indicated by a green flame caused by the formation of a copper halide. The test does not detect fluorine/fluorides.
This test is no longer frequently used. One reason why it is not widely used is that it is possible to generate the highly toxic chloro-dioxins if the test material is a polychloroarene.
An alternative wet test for halide is the sodium fusion test — this test converts organic material to inorganic salts include the sodium halide. Addition of silver nitrate solution causes any halides to precipitate as the respective silver halide.
- F. Beilstein (1872). "Ueber den Nachweis von Chlor, Brom und Jod in organischen Substanzen". Ber. Dtsch. Chem. Ges. 5 (2): 620–621. doi:10.1002/cber.18720050209.
- Barbara M. Scholz-Böttcher; Müfit Bahadir; Henning Hopf (1992). "The Beilstein Test: An Unintentional Dioxin Source in Analytical and Research Laboratories". Angewandte Chemie International Edition in English. 31 (4): 443–444. doi:10.1002/anie.199204431.