COP Standard

Compound

Temperature

                                 LS Mean*

              Day 1          Day 3     Day  5       Day 7

7-ketoa

7-keto tms ether

22+2° C

              166.5            178.8       218.3       228.7

 

 

   4° C

              157.6            169.8       206.6       213.0

 

 

-20° C

              148.5            161.1       203.4       206.4

 

7-keto

       -

                59.3              42.7         10.4         17.6

 

Total 7-keto

       -

              123.4            127.5       141.6        144.3

 

7-keto 3,5-7-oneb

       -

                99.4            112.2        90.6        101.2

19-OHc

19-OH tms ether

       -

              138.1            138.9       169.9       189.6

 

19-OH Related

       -

                63.8             57.3         45.1          44.7

Triold

Triol tms ether

22+2° C

              221.7            330.8       144.4       263.8

 

 

   4° C

              217.1            334.6       143.6       277.2

 

 

-20° C

              218.8            337.1       141.1       275.6

 

Triol related

 

               92.0              80.0         62.7         56.3

a7-ketocholesterol, b7-keto cholesta-3,5-dien-7-one, c19-hydroxycholesterol (19-OH), and dcholestane-3β-5α,6β-triol
Table 2: Stability of COPs over time and temperature: Percent least squares means (LS means of six samples) relative to Day 0 (with value of 100.0). For the for 7-keto tms ether only, temperature was significant (F = 10.45, p = 0.0006) with LS means that decreased as temperature decreased; a significant interaction (F = 4.39, p = 0.0028) between day and temperature was noted. For the triol tms ether, temperature (F = 12.03, p= 0.0005) was significant on day 3.