Organic reagents are used for the qualitative or quantitative determination of chemical elements and for the separation, enrichment and concealment of organic compounds. Organic reagents can be used as indicator, precipitant, titrant, developer, extractant, adsorbent and entrapment agent in analytical chemistry. From the perspective of reaction mechanism, Organic reagents mainly based on the complexation reaction, from a single type of binary divalent chelate complex chelate (see chelation), multi-complex, the scope of application is also growing.
From the beginning of AD to the middle of the 19th century, the main use of natural organic matter (such as animal and plant extracts) qualitative or quantitative analysis. From the second half of the 19th century to the 1920s, artificial reagents began to be synthesized by synthetic organic reagents in the 1930s. After the analysis of functional group theory was proposed in the late 1950s, people searched for functional analysis groups of different ions , Has done a lot of screening of organic reagents, synthesis of a lot of practical value of the reagents (such as copper reagents, copper reagents, cadmium reagents, beryllium reagents, thorium reagents, etc.). Before the 1950s, the complexation chemistry was mainly based on binary chelate precipitation reaction for qualitative detection, precipitation separation and gravimetric analysis. The complexation titration method was mainly used in the early 1950s to the early 1960s. From Beginning in the late 1960s, the emphasis shifted to photometric analysis while evolving chelate organic solvent extraction.