FFA (%)   P1
Test Control
  Exposure time (h) 0 3.500 ± 0.200 3.500 ± 0.200 ns
1 3.500 ± 0.200 3.500 ± 0.200 ns
2 3.500 ± 0.200 3.500 ± 0.200 ns
3 3.503 ± 0.205 3.500 ± 0.200 ns
5 3.503 ± 0.205 3.507 ± 0.200 ns
7 3.510 ± 0.200 3.517 ± 0.220 ns
9 3.513 ± 0.200 3.520 ± 0.220 ns
12 3.520 ± 0.201 3.523 ± 0.225 ns
14 3.540 ± 0.200 3.533 ± 0.215 ns
P2 ns ns  
The values are given as mean ± standard deviation
1Comparison of FFA between essay and control at the same exposure time
2Comparison of FFA between different exposure time
ns: No significant difference at P<0.05
Table 2: Variation of FFA of CPO (assay and control) according to exposure time.