Concentration of protein material is often determined using UV-Visible spectrophotometry wherein the measured absorbance is assumed to be equivalent to the decadic attenuance. The decadic attenuance, D, is computed as the negative logarithm (base 10) of the transmittance, and is analogous to absorbance except for the inclusion of scattering and luminescence effects upon the radiant power exiting the sample . Concentrations reported herein are based on decadic attenuance at 280 nm (D280) with no scatter or luminescence correction. Although the use of decadic attenuance results in an “apparent concentration,” it is most reflective of the experiments commonly performed by the end user (e.g. no scatter or luminescence correction). It should be noted, however, that the D320 has been reported as a means to correct for scattering at 280 nm . Proteins absorb little to no light at 320 nm, and therefore the D320 represents scattered rather than absorbed light. Correction at 280 nm is performed via the Rayleigh scattering equation (intensity of scattered light is proportional to λ−4). This correction becomes increasingly important under formulation conditions inducing colloidal instability. In the current study, D320 was determined to be 0.00222, 0.00287, and 0.00184 (14HB-D-001, 14HB-D-002, 14HB-D-003, respectively) absorbance units which represents a small contribution and is in agreement with the low level of particulates observed using flow imaging as discussed below.