OMB Meeting Book_9-11-14

8 - Identified GC and/or Analyst contributions on the quality of MLT Data

Comment

Fatty Acid

One peak but co-elution is possible (branched fatty acids in dairy)

C15:0, C15:1 n-5, C16:1 n-7, C17:0

Possible presence of two isomers (n-7 or n-8) and possible co-elution (branched fatty acids in dairy)

C17:1 n-

One peak but possible wrong identification or co-elution C18:3 trans isomers

C18:3 n-6 (g)

One peak but presence of other C20:1 isomers ( i.e. dairy) and/or co-elution with C18:3 trans isomers

C20:1 n-9

One peak but possible co-elution with C20:2 n-6 ( i.e. dairy)

C-18:2 CLA

One peak but possible co-elution with CLA isomers ( i.e. dairy)

C20:2 n-6

One peak but possible co-elution or wrong peak identification (e.g. C22:1 n-9)

C20:4 n-6 ARA

Always two peaks (n-9 & n-7) the n-7 cis isomers is naturally present in fats & oils. MUFA and w-9 results can be impacted with error in reporting for C18:1 cis

C18:1 cis

Presence from Δ4 to Δ16 trans isomers (i.e. dairy fat), traces of hydrogenated fat in vegetable oils

C18:1 trans

Various isomers having different origin (i.e. trans in deodorized vegetable oil)

C18:2 trans

Absence in milk, but presence of 2,3 or 4 trans isomers in deodorized vegetable oil and/or possible co-elution with C18:3 n-6 g and C20:1 isomers Sum of C18:1, C18:2 & C18:3 trans The final result can be impacted by individual results reported separately for C18:1 trans , C18:2 trans and C18:3 trans. TFA

C18:3 trans

Absence (or limited) problems for the quantification of: C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C14:1 n-5, C16:0, C18:0, C18:2 cis n-6, C18:3 n-3 (a), C20:0, C20:3 n-6 (dhgla), C20:3 n-3, C20:5 n-3, C22:0, C22:1 n-9, C22:2 n-6, C22:6 n-3, C24:0, and C24:1 n-9