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. Author manuscript; available in PMC: 2019 Jan 31.
Published in final edited form as: Anal Biochem. 2013 Jan 16;435(2):140–149. doi: 10.1016/j.ab.2012.12.021

Figure 2.

Figure 2.

Sample-specific calibration curves for quantitation of BPDE-HSA by ELISA. Each standard or plasma sample is split into pairs of wells to determine ‘background’ (min) and ‘sample’ (y) absorbance readings (see Figure 1). A set of BPDE-HSA standards is used to develop a sigmoid standard curve [Eq. (1)], the shape of which is influenced by the particular background reading (min). The solid curve represents a standard curve obtained from BPDE-HSA standards (in buffer) where min = 0.026 absorbance units, max = 2.7 absorbance units, log(IC50) = 2.53 and Hillslope = 0.5. Having established the standard curve with buffer solutions, the value of min for each plasma specimen is substituted into Eq. (1) to solve for 10x, representing the concentration of BPDE-HSA (ng/mg HSA) in that plasma specimen. The three dashed curves in the figure represent background plasma readings where min = 0.26, 0.76 and 1.1 absorbance units, respectively.