y     time    concentration
48.33  24       0.6 
77.33  24       0.8
78.33  24       1.0
110.67 24       1.2
93.67  24       1.4
131.0  48       0.6 
153.67 48       0.8
188.67 48       1.0
253.67 48       1.2
178.67 48       1.4