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CEC separation of insect oostatic peptides using a strong‐cation‐exchange stationary phase
Author(s) -
Rocco Anna,
Aturki Zeineb,
D'Orazio Giovanni,
Fanali Salvatore,
Šolínová Veronika,
Hlaváček Jan,
Kašička Václav
Publication year - 2007
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200600452
Subject(s) - chemistry , ionic strength , phase (matter) , chromatography , resolution (logic) , sulfonic acid , analytical chemistry (journal) , selectivity , buffer (optical fiber) , buffer solution , aqueous solution , organic chemistry , telecommunications , artificial intelligence , computer science , catalysis
Abstract The separation of several insect oostatic peptides (IOPs) was achieved by using CEC with a strong‐cation‐exchange (SCX) stationary phase in the fused‐silica capillary column of 75 μm id. The effect of organic modifier, ionic strength, buffer pH, applied voltage, and temperature on peptides' resolution was evaluated. Baseline separation of the studied IOPs was achieved using a mobile phase containing 100 mM pH 2.3 sodium phosphate buffer/water/ACN (10:20:70 v/v/v). In order to reduce the analysis time, experiments were performed in the short side mode where the stationary phase was packed for 7 cm only. The selection of the experimental parameters strongly influenced the retention time, resolution, and retention factor. An acidic pH was selected in order to positively charge the analyzed peptides, the p I 's of which are about 3 in water buffer solutions. A good selectivity and resolution was achieved at pH <2.8; at higher pH the three parameters decreased due to reduced or even zero charge of peptides. The increase in the ionic strength of the buffer present in the mobile phase caused a decrease in retention factor for all the studied compounds due to the decreased interaction between analytes and stationary phase. Raising the ACN concentration in the mobile phase in the range 40–80% v/v caused an increase in both retention factor, retention time, and resolution due to the hydrophilic interactions of IOPs with free silanols and sulfonic groups of the stationary phase.