Use of the sol-gel technique to prepare capillary columns coated with a macrocyclic dioxopolyamine for open-tubular capillary electrochromatography

Columns for open-tubular (OT) capillary electrochromatography (CEC), coated with 1,4,7,10-tetroazacyclotridecane-11,13-dione (dioxo[13]aneN(4)) by use of the sol-gel technique, have been investigated for the first time. Dioxo [13]aneN4 was reacted with 3-(2-cyclooxypropoxy)propyltrimeihoxysilone and the product was then mixed with tetraethoxysilane (TEOS) and water to form a glass matrix as a network in which the stationary phase (dioxo[13]aneN(4) ) was incorporated. In comparison with OTCEC columns prepared by the sol-ge l process with TEOS only, the sol-gel-derived macrocyclic dioxopolyamine co lumns enabled better separations of a mixture of isomeric nitrophenols and benzenediols, a mixture of isomeric aminophenols and diaminobenzenes, and a mixture of four biogenic monoamine neurotransmitters. High efficiencies (6 0 000-340 000 plates m(-1)) were achieved,for isomeric benzenediols, aminop henols, nitrophenols, and diaminobenzenes. Migration time and theoretical p late number reproducibility was satisfactory; RSD was <2% for one column an d <8.5% from column to column.