FIG. 2.

Spectrophotometric absorbance as a function of collagen concentration. Sircol collagen standard at different concentrations was quantified via hydroxyproline assay using DMAB dissolved in a solution consisting of isopropanol and strong acid (30% HClO₄, 10% HCl, 30% HCl, or 50% HCl). The HClO₄ group generated a curve with the greatest slope. For the groups using HCl, a 30% strong acid solution most closely mimicked the results of HClO₄ and displayed the greatest linearity. These two groups were carried forward into later phases of this project for further comparison. HCl, hydrochloric acid; HClO₄, perchloric acid.