SAMPLE CONSIDERATIONS FOR AMINO ACID ANALYSIS
Adequate sample purification is essential for accurate compositions and quantitative data. Unfortunately, even the purification protocols used can contribute both to sample contamination and loss. There are numerous factors to consider when trying to prevent sample contamination. Reagent or solvent solutions, glassware, pipetting devices, dust, fingers or anything else that comes in contact with the sample may introduce background free amino acids or proteins. The entire sample handling environment must be scrupulously clean for high sensitivity analysis.
Tips to help reduce Amino Acid Sample Contamination
Samples Submitted for
Amino Acid Analysis
|Additive||Effects and % Recovery|
|Ammonium acetate||No negative effect|
|Sodium acetate||His and Cys~50%; Ile, Leu, Phe and Lys ~80%|
|Triethylammonium acetate||His, Thr and Phe ~90%|
|Ammonium bicarbonate||Thr ~90%|
|Sodium bicarbonate||Met ~40%; His, Tyr ~60%; Ile, Leu, Phe and Lys ~80%|
|Sodium borate||No negative effect on result|
|Sodium chloride||No negative effect on result|
|Sodium phosphate||Very low and variable yields of most amino acids|
|Triethylammonium phosphate||No negative effect on result|
|CAPS||Very large late eluting peak obscures Phe, Lys|
|HEPES||Gives artifact peak which co-elutes with Met|
|TRIS||His ~60%, artifact peak co-elutes with Tyr|
|SDS||His and Thr ~90%, Cys and Lys ~110%|
|Triton X-100||His and Thr ~90%, Cys and Lys ~110%|
Taken From : Applied Biosystems 420/H Users Manual, Table 2-2
Amino Acid Analysis has also proven valuable for the
analysis of biotinylated peptides and proteins as well.
See: Smith, J.S., Miller, B.T.,
Knock, S.L., and Kurosky, A. Biotinylated peptides/proteins: I. Determination of
stoichiometry of derivatization. Analyt. Biochem. 197:247-253, 1991.
For more information on preparing samples for amino acid analysis, or if you have a sample for analysis, contact :
Rm 2.226 Basic Science Bldg.
E - mail :firstname.lastname@example.org