The foundations of Feigls work on spot analysis were the works of Hugo Schiff (the earliest publication about "spot test" was Shiffs detection of uric acid in 1859) and of Christian Friedrich Schonberg and Friedrich Goppelsröder on capillary analysis.
On the occasion of Feigl's 70th birthday the Chemical Society of Midland sponsored a symposium in 1952, attended by 500 scientists from 24 countries, in which all plenary sessions were related to spot tests.
The test uses the qualitative characteristics of colored compounds to account for performed chemical reactions. This technique has been used to develop new quantification methods using modern technology.