Problem 14.4

a) Consider the GC-MS measurement of a mixture of carboxylic acid methyl-, ethyl- and propyl esters containing the range from C10 to C18 acids. The measurement was performed in the repetitive scanning mode.
Suggest single or multiple RICs to identify:

  1. Only methyl esters
  2. Only ethyl esters
  3. Only palmitic acid methylester   

b) Using this GC-MS data, could you identify palmitic acid methyl ester from a single m/z trace?

c) Aliphatic alcohols yield no or extremely weak molecular ion peaks in EI-MS. For GC-MS, they are often converted into their trimethylsilyl derivatives which form a characteristic ion at m/z 73. What is the m/z 73 ion and why shouldn’t it be used as a tracer for alcohols in GC-MS?

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