Fritz Feigl is the creator of "spot analysis" (spot test),[1][2] a simple and efficient technique where analytic assays are executed in only one, or a few drops, of a chemical solution, preferably in a great piece of filter paper, without using any sophisticated instrumentation.

A notable example he developed was a simple test to know if fishes eaten by Amazon population are contaminated by lead.

Poor populations by the Amazon rivers were taught to easily use that technique to find out contaminated fishes and discharge them.

On the occasion of Feigl's 70th birthday the Chemical Society of Midland sponsored a symposium in 1962,[3] attended by 500 scientists from 24 countries, in which all plenary sessions were related on spot tests.

[1] A less known contribution is the development of "luminol", a substance used by forensic investigators to detect the presence of blood, even if the scene has been washed and cleaned.