Ninhydrin Positive Substances Present in Official Amino Acids

NINHYDRIN POSITIVE SUBSTANCES PRESENT IN OFFICIAL AMINO ACIDS 

Materials Required Silica gel-G mobile-phase (glacial acetic acid water butan-l-ol 20 20 20 60) 100 ml solution (1) dissolve 0.1 g of sample in 5 ml of 2 M ammonia solution (2) dilute 1 ml of soln. (1) to 50 ml with water solution (3) dilute 5 ml of solution (2) to 20 ml with water Solution (4) dissolve 10 mg of glutamic acid EPCRS in sufficient water to produce 50 ml solution (5) dissolve 10 mg of glutamic acid EPCRS and 10 mg of aspartic acid EPCRS in sufficient water to produce 25 ml ninhydrin solution (0.2% w/v solution of ninhydrin in a mixture of 95 vols. of butan-l-ol and 5 vols of 2 M acetic acid ) 50 ml  

Procedure Apply separately to the silica gel G coated plates 5 pi of each of sols (1), (2), (3), (4) and (5) and dry the TLC plates in a current of air for 15 minutes before commencing development. Carry out the development using the above mentioned mobile-phase as usual. After removal of the plate, allow it to dry in air, spray with ninhydrin solution and heat at 100° to 105 °C for 15 minutes. 

The assay of leucine-an amino acid official in BP (1993) may also be carried out by adopting a similar procedure using the same adsorbent and mobile-phase but different solution from (1) to (5). 

Attempt the following aspect of Thin-layer Chromatography (TLC)  

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Ninhydrin positive substances present in official amino acids... 

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