Figure 6

Intrinsic fluorescence emission spectra (540–580 nm) of 20 μg/mL LDH in 0.2 M Tris–HCl buffer (pH 7.4) after the freeze–thaw process was repeated five times. LDH solution was frozen at a freezing rate of 0.2, 12.8, or 70.6º C/min. The frozen samples were thawed in a water bath at 25 ºC for 5 min before analysis.