Monitoring of Arrays of Amino Acids in Clinical Samples Using Capillary Electrophoresis with Contactless Conductivity Detection

Capillary electrophoresis (CE) with contactless conductivity detection (C⁴ D) is readily applicable to determinations of amino acids in clinical samples. Most of these analyses employ long separation pathways. This chapter describes CE/C⁴ D determinations of 28 biogenic amino acids in a short capillary with an effective length of 18 cm. All the test amino acids can be mutually separated in electrolytes of 0.5–10 mol/L acetic acid. The time of analysis does not exceed 6 min; the limits of detection vary from 0.1 to 1.7 μmol/L for all the analytes. The pretreatment of the biological material is very simple, consisting of the removal of proteins by an addition of acetonitrile and subsequent filtration. The procedure has been successfully applied to determinations of the whole amino acid spectra in blood plasma, urine, saliva, cerebrospinal, and amniotic fluid samples.