Well, I give a few names:

DSC - differential scanning calorimetry for collagen gels

FT-IR - for protein band analysis

CD - circular dichroism for assessing triple-helix in collagen solutions

Also FTIR- and CD-Spectroscopy gives insight into secondary structure and monomer/triple helices formation.

I'm curious about this question, too. Since I'm not from either life science or chemistry related backgrounds, what I know basically is that collagen fibers have a 67-nm periodicity due to the staggered arrangements of the molecules with triple helix. I just wonder if the 67-nm periodicity could be a determinant characteristic for collagen fibrils? In other words, could I claim that the fibers I observed under microscopes (SEM, TEM, AFM, etc.) is 100% collagen just because it contains the 67-nm periodicity?

@chang - Your information is partially correct - there are many types of collagen and all of them do not have the same periodicity.

@Senthil - I would suggest mechanical and imaging methods - mechanical methods to show strength of collagens at either macro (mechanical testing) or nano (AFM) levels. Imaging - Starting from Histology to SEM or TEM (as suggested by @Chang).

Regarding nano-scale mechanics of collagen (in cartilage) you might want to look at a couple of our papers here on RG:

https://www.researchgate.net/publication/232748308_Early_detection_of_aging_cartilage_and_osteoarthritis_in_mice_and_patient_samples_using_atomic_force_microscopy?ev=prf_pub

https://www.researchgate.net/publication/44640571_Micro-_and_nanomechanical_analysis_of_articular_cartilage_by_indentation-type_atomic_force_microscopy_validation_with_a_gel-microfiber_composite?ev=prf_pub

Article Early detection of aging cartilage and osteoarthritis in mic...

Article Micro- and Nanomechanical Analysis of Articular Cartilage by...

Here is also one from our institute based on CD-Spectroscopy.

Best regards,

Martin Müller

U. Freudenberg, S.H. Behrens, P.B. Welzel, M. Müller, M. Grimmer, K. Salchert, T. Taeger, K. Schmidt, W. Pompe, C. Werner, Electrostatic interactions modulate the conformation of collagen I, Biophysical Journal, 92, 2108-2119 (2007)