Hypothetical example. You have received a new molecule where someone tried to develop a liquid formulation, but was not able to provide adequate stability. Their best formulation contained 20 mg/mL protein (5%) in 20 mM histidine (0.3%), 85 mM NaCl (0.5%), 3% sorbitol, pH 6.0.

What is the glass transition temperature of this formulation (assume Tg' of protein is -10 C, sodium chloride is -120 C). Only enter the number (to one decimal place) in degrees C (exclude the units).