Trace level determination of substance P using capillary electrophoresis and laser-induced fluorescence

• Published in: Microchemical journal Vol. 78; no. 2; pp. 135 - 142
• Main Authors: Frerichs, Valerie A., Herrmann, Jennifer K., Aguirre, Alfredo, Colón, Luis A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2004
• Subjects: Capillary electrophoresis; Laser-induced fluorescence; NDA derivatization; Saliva samples; Substance P; Laser-induced fluorescence; NDA derivatization; Capillary electrophoresis; Substance P; Saliva samples
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2004.03.018

An analytical method was developed to determine the undecapetide substance P (SP) based on capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. SP was derivatized with the fluorogenic reagent 2,3-naphthalenedicarboxaldehyde (NDA) prior to injection into the CE-LIF system. The pre-column derivatization scheme combined with injection enhancement techniques extends the detectability of SP to the subnanomolar level. Limit of detection (LOD) of 100 pM was achieved without pre-concentrating the sample prior to injection. The reproducibility for six different preparations of a standard sample containing 5 nM of SP was 6.8% RSD and that of the CE migration time was 0.08% RSD. The method was used to determine SP in a saliva sample.