AccQ-Tag and MassTrak running on an Acquity UPLC (Waters)

Analysis	Minimum Recommended Amount	Optimal Amount	Notes
Amino acid composition and concentration of proteins/peptides (incl. hydrolysis in 6 M HCL)	1 ug (lower amounts may still give some results but at a significantly reduced accuracy)	2 – 10 ug	Ideally, sample should be free of non-volatile salts, buffers, primary amines and detergents. A small amount of buffer is compatible with the pre-column reaction as long as it does not alter the pH of the reaction (40 ul 0.2 M borate, pH 8). Primary and secondary amines react with the reagent and their products may co-elute with amino acid derivatives (e. g. the reaction product of Tris co-elutes with Ser)
Free amino acids (without hydrolysis)	50 ul	100 – 200 ul	Volumes indicated are for mouse urine and plasma; they may be significantly different for other species or for tissue extract.Do not perform SSA precipitation, this should be carried out immediately before analysis.