Premium
Esterified alkan‐1‐ols and alkan‐2‐ols in barley epicuticular wax
Author(s) -
WettsteinKnowles P.,
Netting A. G.
Publication year - 1976
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02532839
Subject(s) - wax , epicuticular wax , chemistry , wax ester , alcohol , moiety , chromatography , silica gel , mass spectrometry , column chromatography , composition (language) , organic chemistry , philosophy , linguistics
The epicuticular wax on all barley organs is characterized by the presence of long chain esters which have alkan‐1‐ols as their alcohol moiety (mainly C 38 −C 48 ). A second type of long chain ester in which alkan‐2‐ols serve as the alcohol moiety has been identified in the wax from all organs except the awns and leaf blades (mainly C 33 −C 35 ). Utilizing Silica Gel H column chromatography, a 95% separation of the two ester types was achieved. Unlike alkan‐1‐ols, the alkan‐2‐ols (primarily C 13 and C 15 ) do not occur free in the wax. Esters isolated from spike minus awn wax consisted of 62% alkan‐2‐ol and 38% alkan‐1‐ol containing esters. The isomeric composition of each ester was determined with the aid of gas liquid chromatography‐mass spectrometry. In the mass spectra of the alkan‐2‐ol containing esters, mass ions were absent and the relative intensities of the RCO 2 H 2 + , RCO 2 H + , [R′‐1] + , and RCO + ions were markedly different from those characteristic for alkan‐1‐ol containing esters. Since esterified alkan‐2‐ols occur only in those waxes having β‐diketones, a close biosynthetic relationship between these two lipid classes is suggested.