Dual fluorescence and electrochemical detection on an electrophoresis microchip.
Simultaneous amperometric and fluorescence detection in a microfabricated electrophoresis chip is reported. Detection limits of 448 nM and 1.52, 16, and 28 microM have been achieved for dopamine, catechol, NBD-arginine, and NBD-phenylalanine, respectively. These two orthogonal detection schemes allow analysis of a wider spectrum of compounds per separation, leading to higher throughput and enabling resolution of two neutral analytes, NBD-arginine and catechol. In addition, insight into the detection and separation mechanisms is realized. Differences in migration time and peak widths between the two detectors are compared, providing a better understanding of detector alignment. A common problem encountered in electrophoresis is run-to-run migration time irreproducibility for certain samples. This novel microchip dual detection system has been utilized to reduce this irreproducibility. An unknown sample is monitored with one detector while a standard (i.e., ladder) is added to the sample and monitored simultaneously with the other detector. This dual detection method is demonstrated to normalize unknown peak mobilities in a cerebral spinal fluid sample.
Lapos
Julie A
JA
Department of Chemistry, Pennsylvania State University, University Park 16802, USA.
Manica
Drew P
DP
Ewing
Andrew G
AG
D009327:4-Chloro-7-nitrobenzofurazan; D001120:Arginine / Q000032:analysis; D002396:Catechols / Q000032:analysis; D004298:Dopamine / Q000032:analysis; D004563:Electrochemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D005453:Fluorescence; D018698:Glutamic Acid / Q000032:analysis; D006801:Humans; D007202:Indicators and Reagents; D009103:Multiple Sclerosis / Q000134:cerebrospinal fluid; D010649:Phenylalanine / Q000032:analysis
D002396:Catechols; D007202:Indicators and Reagents; D018698:Glutamic Acid; D010649:Phenylalanine; D001120:Arginine; D009327:4-Chloro-7-nitrobenzofurazan; C034221:catechol; D004298:Dopamine