(A) Monocyanocobinamide response to 5.0 ppm HCN exposure on glass fiber filter paper as a function of time of exposure. CN(H2O)Cbi before HCN (solid line), 1 min of exposure (dotted line), 5 min of exposure (short dashed line), 10 min exposure (long dashed line) and 15 min exposure (hollow line). (B) Diffuse reflectance spectra when the reflectance spectrum of CN(H2O)Cbi on glass fiber filter paper was designated as the “blank” (solid line), 1 min exposure (dotted line), 5 min exposure (short dashed line), 10 min exposure (long dashed line) and 15 min exposure (hollow line).