In the arsenal of biophysical techniques available for rapidly monitoring the stability of protein formulations, spectroscopic techniques have some convincing advantages over others (1, 2). The main advantages to using methods such as circular dichroism (CD), infrared spectroscopy (IR) and fluorescence spectroscopy are their extremely high sensitivity (favorable signal-to-noise ratios), freedom from sample interactions with column resins or extrinsic probes (noninvasive techniques), and coverage of an extremely broad protein concentration range — from pM to mM (3, 4). To reduce…