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.