What Does
Sodium Sulfide Spot Test Mean?
A sodium sulfide spot test is a localized chemical test to detect any concentration of lead in a coating substance by the application of sodium sulfide to the coating’s surface.
Corrosionpedia Explains Sodium Sulfide Spot Test
Sodium sulfide spot tests are performed in a qualitative manner by applying the sodium sulfide to a given coating’s surface and waiting to observe the formation of a black or gray colored spot. The presence of either of these colors is a result of a chemical reaction between lead and sulfide reactants; therefore, the test serves as an indicator of the presence of lead in the coating.