Determination of L-arginine in amniotic fluid by capillary zone electrophoresis

Conditions for the determination of L-arginine in a biological fluid using capillary zone electrophoresis were optimized. The effects of the pH of a running buffer, the time of sample injection into a capillary, the operating voltage, the temperature, and the wavelength on the results of the determination were studied. The procedure made it possible to evaluate the concentration of L-arginine over a range of 6–1000 μg/mL ( c = 3 μg/mL; RSD = 2%). The duration of analysis including sample preparation was no longer than 30 min. The analysis of amniotic fluid samples in the cases of physiological pregnancy and pregnancy complicated by placental insufficiency demonstrated that the arginine content of amniotic fluid increased in the case of placental insufficiency, as compared to normal values.