Small peptides can also be separated by HPLC or UPLC on a reverse phase column or size exclusion column.

If you don't know anything else about the peptide, the best alternative could be Size Exclusion Chromatography (analytical SEC) using U(HPLC) columns.

The technique pumps a pressurized liquid solvent containing the sample through a chromatography column filled with a solid adsorbent highly porous matrix.

Thus, the molecules elute in decreasing order of apparent size (mass and shape/lenght).

Once separated, the sample molecules’ sizes can be confirmed using 2 methods:

• Calibration curve: Various molecules of known size are injected onto the same column as the sample. The retention time of each component is obtained from the calibration chromatogram and plotted against the logarithmic molecular mass.
• Static light scattering: Molecular masses are calculated of a light scattering signal and a refractive index signal and are independent of the hydration shell thickness of the molecules.

Poster Size Exclusion Chromatography

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Why are you looking for alternatives, if I may ask? In my experience, besides the limited shelf-life of precast gels, Tricine works very well for electrophoresis in exactly this range.

If you must separate via electrophoresis, and tricine is unacceptable, then you might try isoelectric focusing.

Dr. Shapiro is right, though: HPLC is the standard for peptide separations.

no may be gel filtration or HPLC

Peptides can be separated on SDS-PAGE and probably by PAGE. The problem is how to detect them especially if they are small . If you try to stain them with a dye they may be washed out of the gel during the fixing/staining procedure . If you can label the peptides with a fluorophor before the electrophoresis then you will be able to detect them by illumination of the gel with light of a suitable wavelength whilst they are still in the glass gel cassette.

If a tris/tricine buffer does not work well then use a tris-glycine/trisHCl buffer system ( Laemmli method) You may need to use a high concentration of acrylamide . Best to use a gradient in initial work : try 10-30% or 20-40% acrylamide .