K. Lemr et al., REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SEPARATION OF 1-NAPHTHYL ISOCYANATE DERIVATIVES OF LINEAR ALCOHOL POLYETHOXYLATES, Journal of chromatography, 686(2), 1994, pp. 219-224
The optimization procedure for the reversed-phase HPLC separation of 1
-naphthyl isocyanate derivatives of linear alcohol polyethoxylates (LA
Es) is reported. Using a C-18-bonded silica stationary phase and aceto
nitrile-water mixtures as mobile phase, different trends in the chroma
tographic separation of selected 1-tetradecanol polyethyleneglycol eth
er ethoxymers were observed. In the investigated range of acetonitrile
-mobile phase volume ratio (phi), the elution order of the ethoxymers
was inverted by increasing the organic solvent content of the mobile p
hase, and the mobile phase composition was found which provides the co
-elution of the tested compounds. On the basis of the trends of capaci
ty factor logarithm (log k') versus the number of ethoxy units (n) at
different phi, an increased retention by increasing phi. was also pred
icted for higher ethoxymers. The separation under the same chromatogra
phic conditions of a C-12-C-18 LAE mixture with an average number of 1
0 ethoxy units, confirmed the strong variability of LAE chromatographi
c behaviour in the investigated cp range. The isoeluting conditions fo
und for the C-14 LAE ethoxymers were also applied successfully to the
homologue-by-homologue separation of the C-12-C-18 LAE mixture.