y     time    concentration
49.00  24       0.6 
64.00  24       0.8
80.67  24       1.0
113.00 24       1.2
94.67  24       1.4
116.33 48       0.6 
132.00 48       0.8
127.33 48       1.0
190.33 48       1.2
194.33 48       1.4