Qualitative tests for Carbohydrates Flashcards
General Tests for CHO
Molisch test and Anthrone test
reagent: 𝛼-naphthol + H2SO4
Molisch test
reagent: anthrone
Anthrone test
Violet ring at the junction (+) for CHO
Molisch test
Green color (+) for CHO
Anthrone test
Reagent: CuSO4 + Na2CO3 + Na citrate
Benefict’s
Test for reducing sugars
- Fehling’s
- Benedict’s
- Barfoed’s (Differentiates mono vs di)
- Tollen’s
- Maillard’s
Reagent: CuSO4 + Na-K tartrate
Fehling’s
Reagent: Ammoniacal AgNO3
Tollen’s
Reagent: CuSO4 + acetic acid
Barfoed’s
Brick red ppt (+) For reducing sugars
- Fehling’s
- Benedict’s
- Barfoed’s (mono: <5mins vs di: >15mins)
Reagent: Amino acids
Maillard’s
Silver mirror (+) For reducing sugars
Tollen’s
Brown coloration (+) For reducing sugars
Maillard’s
Test for ketoses
Seliwanoff’s
Test for Pentoses
Bial’s and Tollen’s Phloroglucinol
Reagent: Recorcinol, HCl
Seliwanoff’s
Reagent: Orcinol, HCl
Bial’s
Reagent: Phlolorglucinol
Tollen’s phloroglucinol
Blue-green color (+) pentoses
Bial’s
Pink / Cherry red (+) ketoses
Seliwanoff’s
Red (+) pentoses
Tollen’s phloroglucinol
Test for starch and glycogen
Iodine test
Reagent: Iodine
iodine test