Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone functional groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' reagent test. The test was developed by German chemist Hermann von Fehling in 1849.
A species model for the copper(II)/L-(+)-tartaric acid (LH2, tartH2) aqueous system between pH 1.9 and 12.3 has been established by potentiometric, UV/Vis spectroscopic, solubility and crystallographic studies
Fehling's test is used to distinguish between the presence of aldehydes and ketones in carbohydrates as ketone sugars except alpha-hydroxy-ketone do not react in this test. Fehling's test is performed in medical facilities to detect the presence of glucose in urine
