SEPARATION, IDENTIFICATION AND QUANTIFICATION OF MONOMERS FROM CUTIN POLYMERS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND EVAPORATIVE LIGHT-SCATTERING DETECTION

A silicic acid high performance liquid chromatographic method which utilizes an evaporative light scattering detector has been developed for the separation of cutin monomers. This binary gradient system was successfully applied to separate underivatized monomers of several fruit cutins including those from apple cvs. Golden Delicious and Red Delicious (Malus pumila), tomato (Lycopersicon esculentum), grapefruit (Citrus paradisi) green pepper (Capsidum annum) and pumpkin (Cucurbila pepo). All cutin monomers, from the least polar, monohydroxy saturated and unsaturated fatty acids, to the most polar, trihydroxy saturated and unsaturated fatty acids, were separated. Monomer identity was confirmed by gas chromatography-mass spectromety of collected peaks. The gradient was also able to separate positional isomers of dihydroxy fatty acids, a separation not yet achieved by gas chromatography. The relationship between detector response and the mass of five common cutin monomers was obtained.