There are several samples which is believed that glycine is incorporated in them. I must know the exact quantitative amount of the glycine in the sample?
What would be the most suitable way to perform the test?
Kaiser test (ninhydrine test) is thought at first to detect the primary amine.
What could be the other alternatives?
Just an idea to be put into practice for a lab without any further sophisticated equipment out of a precision balance and a few other tools and equipment. Digest your sample so that the proteins are fully decomposed into amino acids. Adjust the pH-value with a suitable buffer used for the following chromatography and which can be removed later on.
Perform a one or two dimensional thick-film chromatography with a known amount of sample so that your glycine reaches up to approximately 50 mg in the spot, which should be fully separated from other spots (check with ninhydrine and a selective spectroscopic method). Extract/scratch the spot quantitatively from the glass plate. Remove the solid chromatography material. Let the solvent to evaporate without loss or contamination of your analyte. Check with IR or other spectroscopic or chromatographic method the purity of the analyte (L-glycine). Weigh your sample in a crucible or other suitable container with a precision balance able to indicate at least a few micrograms. Use proper corrections for air buoyancy.
Certainly there are other many more modern methods, but if the use of gravimetry is the goal you will get excellent values. Your chromatography and your extraction procedure must be flawless. It needs some time to elaborate the procedure. The chromatography must be optimised and a perfect separation of L-glycine from other sample ingredients must be achieved.
I think you can quantify glycine with and without derivatization by HPLC.
The above method is the poor peoples procedure, with almost no equipment out of a balance and a few other instruments. For checking the amino acid separation you need an amino acid mixture of known composition.
Amino-acid analysis is a standard procedure if you have a HPCL you can do the analysis described in the following publication:
'Amino acid analysis for pharmacopoeial purposes', Oliver Wahl, Ulrike Holzgrabe, Talanta (2016), 154, 150-163.
There is also a standard thin layer test method described in European Pharmacopoeia 9.0 (2.2.56, p.93). This method hardly gives you good quantitative results.
- Badges
- Science topic
- Similar topics
- Cognitive Science
- Thinking