[cH5 H]CH2 CH(CH5国 CH3CH2CH! t CH3CHCH3 e43 十 i CH3.+ CH3CH2 CH2 CHCH3 e71 CH3CH2·+(CH3)2CHCH2CH3 CH2 CH2 CH(CH3 )CH3 +. CH3 CH2 CH2 . + CH3 CHCH3 + m/e 43 CH3 . + CH3 CH2 CH2 CHCH3 + m/e 71 CH3 CH2 . + (CH3 ) 2 CHCH2 + m/e 57 CH3 CH2 CH2 CH(CH3 )CH3 +. CH3 CH2 CH2 . + CH3 CHCH3 + m/e 43 CH3 . + CH3 CH2 CH2 CHCH3 + m/e 71 CH3 CH2 . + (CH3 ) 2 CHCH2 + m/e 57