The partitioning of a set of 14 primary, secondary and tertiary alkano
ls with chain-lengths ranging from C1 to C6 in the three-phase system
plant cuticle, water and atmosphere was investigated. A static headspa
ce gas chromatographic method was devised for measuring the distributi
on of the volatile alkanols between the gas, cuticle and aqueous phase
s, respectively. Measurements were performed in the temperature range
from 5-40 degrees C. The isotherms for the sorption of alkanols in the
cuticular polymer matrix (MX) obeyed Henry's law and, at 25 degrees C
, molal MX/air partition coefficients (K-MXa) ranging from 454 (methan
ol) to 33 000 (1-hexanol) were obtained from their slopes. The corresp
onding experimental air/water partition coefficients (K-aw) varied fro
m 1.94 x 10(-4) (methanol) to 8.47 x 10(-4) (2-hexanol). MX/water part
ition coefficients (K-MXw) in the range from 0.088 (methanol) to 23 (1
-hexanol) were estimated from K-MXa and K-aw. On average, K-MXa was re
duced by a factor of two when temperature increased by 10 K. A common
reduced isotherm was obtained for all compounds (except methanol) and
all temperatures when the concentrations in the MX were plotted versus
the ratios of the actual and the saturation vapour pressures. A serie
s of quantitative property/property and structure/property relationshi
ps between the parameters for partitioning and simple physico-chemical
properties and structural descriptors of the alkanols was established
.