Sørensen formol titration
Titration of amino acid
From Wikipedia, the free encyclopedia
The Sørensen formol titration(SFT) invented by S. P. L. Sørensen in 1907 [1][2] is a largely archaic method that was once used to determine the amino acid content of a sample. It is used in the determination of protein content in samples.[3]
In case of tyrosine, the actual results are too high due to the negative hydroxyl group (-OH), which acts as a base. This explanation is supported by the fact that phenylalanine can be accurately titrated.[2]
Method
The titration of an amino acid with potassium hydroxide in the presence of formaldehyde.[4]
In winemaking
Formol titration is used in winemaking to measure yeast assimilable nitrogen needed by wine yeast in order to complete fermentation.[5] A related analysis method is o-phthaldialdehyde/N-acetyl-L-cysteine spectrophotometric assay (NOPA).[6]
