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Qualitative tests of Carbohydrate Discussion. September 5, 2005 A. Apirakaramwong. Result. Anthrone Molisch Glucose green purple ring Fructose green purple ring Arabinose green purple ring Maltose green purple ring Sucrose green purple ring Starch green purple ring
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Qualitative tests of CarbohydrateDiscussion September 5, 2005 A. Apirakaramwong
Result Anthrone Molisch Glucose green purple ring Fructose green purple ring Arabinose green purple ring Maltose green purple ring Sucrose green purple ring Starch green purple ring Dextrin green purple ring (+) (+)
Result Bial’s Seliwanoff Glucose brown colorless Fructose brown orange Arabinose green colorless Maltose brown colorless Sucrose brown very pale pink Starch brown colorless Dextrin brown colorless (+) green(+) orange
Result Benedict Iodine Glucose +++ yellow Fructose ++++ yellow Arabinose +++ yellow Maltose ++ yellow Sucrose _ yellow Starch _ blue Dextrin + red purple (+) red brick ppt(+) blue, red purple
+ve (carbohydrate) -ve (not carbohydrate) +ve (polysaccharide): starch, dextrin -ve (not polysaccharide) Summary Sample Molisch, Anthrone’s test Iodine test
+ve (reducing sugar) -ve (non-reducing sugar) : sucrose -ve (not polysaccharide) Benedict’s test Bial’s test +ve (pentose): arabinose -ve (hexose) Seliwanoff’s test +ve (ketose): fructose -ve (aldose): glucose, maltose
Qualitative tests of Proteins and amino acidsDiscussion September 5, 2005 A. Apirakaramwong
Result Biuret Ninhydrin Gelatin purple purple (~5-10min) Casein purple colorless-yellow Urea pink colorless Tyrosine light blue purple (~10 min) Phenol light blue colorless Glycine light blue purple (<5 min) Proline light blue yellow (<5 min) (+) pink, purple (+) purple, yellow
Result Xanthoproteic Millon’s Gelatin yellow red Casein yellow pink-red ppt Urea colorless white ppt Tyrosine deep yellow red Phenol orange dark red Glycine colorless colorless Proline colorless colorless (+) yellow-orange (+) pink-red
Summary Sample Biuret test +ve (protein): casein, gelatin if give pink color may be urea -ve (not protein, may be amino acid) Ninhydrin (confirm, optional) Ninhydrin -ve (not composed of amino acid): urea +ve (composed of amino acid): casein, gelatin -ve (not amino acid): phenol +ve (amino acid): glycine, tyrosine, proline Xanthoproteic or Millon’s +ve
Identification of Biomolecules (1) • Unknown sample 1 tube (15 mL) • Write down no. of sample on the answer sheet • Rm 410: carbohydrate reagents • Rm 406: protein and amino acid reagents • Precaution: do not chat or discuss with others, otherwise you will be asked to stop all process and get out from the lab (terminate the exam with no exception)
Identification of Biomolecules (2) • Unknown sample 1 tube (15 mL) • please write down no. of sample on the answer sheet • Rm 410: carbohydrate reagents • Rm 406: protein and amino acid reagents • Precaution: do not chat or discuss with others, otherwise you will be asked to stop all process and get out from the lab (terminate the exam with no exception)