4
Challenges of Phenolic Analysis
•
Multiple Analytes – > 8000 known compounds
•
Lack of Standards – Many compounds are not
available as commercial standards.
d d
i
d f
i
i
•
Stan ar s are expens ve an o uncerta n pur ty
•
Many are unstable, particularly for quantitative
analysis
Folin‐Ciocalteu Assay
•
Developed by Folin and Denis 1912 to measure
tyrosine
•
Originally developed as an analysis for protein by
Folin in 1927
WO
4
2‐
/ MO
4
2‐
+ Tyrosine –OH Blue color
•
Folin‐Ciocalteu (1927) added Lithium Sulfate and
Bromine to reaction mixture to prevent precipitate
formation
•
Adopted for phenolics in wine by Singleton 1999
