N. Nishimura et al., Application of capillary electrophoresis to the simultaneous determinationof betaines in plants, ANAL SCI, 17(1), 2001, pp. 103-106
The simultaneous determination of betaines, the key compounds for osmotic r
egulation in plants, was established by capillary electrophoresis (CE). Aft
er four betaines, glycine betaine (GB), beta -alanine betaine (AB), proline
betaine (PB), and 2-hydroxyproline betaine (HPB), were esterified with p-b
romophenacyl bromide, the esters were electrophoresed in 100 mM sodium phos
phate at pH 3.0. A low-pH condition in CE and esterification gave an advant
age of resolving each of the ester peaks as well as those of the unreacted
reagent and other components. Furthermore, the addition of 4% polyethylene
glycol (PEG) gave a better resolution of 4 peaks, resulting in the separati
on of the overlapped peaks of PB and AB. It was found from the standard add
ition method being applied to barley leaves that the GB content in plants c
ould be evaluated by using a calibration curve of the GB standard solution.
The extraction of GB from plant leaves was also improved by adopting water
as the extraction solvent instead of a mixture of organic solvents. The pr
esent method was suitably applied to actual plant specimens collected from
a saline area of China.