Electrophoretic analysis of biomarkers using capillary modification with gold nanoparticles embedded in a polycation and boron doped diamond electrode.
Field-amplified sample stacking using a fused silica capillary coated with gold nanoparticles (AuNPs) embedded in poly(diallyl dimethylammonium) chloride (PDDA) has been investigated for the electrophoretic separation of indoxyl sulfate, homovanillic acid (HVA), and vanillylmandelic acid (VMA). AuNPs (27 nm) exhibit ionic and hydrophobic interactions, as well as hydrogen bonding with the PDDA network to form a stable layer on the internal wall of the capillary. This approach reverses electro-osmotic flow allowing for fast migration of the analytes while retarding other endogenous compounds including ascorbic acid, uric acid, catecholamines, and indoleamines. Notably, the two closely related biomarkers of clinical significance, HVA and VMA, displayed differential interaction with PDDA-AuNPs which enabled the separation of this pair. The detection limit of the three analytes obtained by using a boron doped diamond electrode was approximately 75 nM, which was significantly below their normal physiological levels in biological fluids. This combined separation and detection scheme was applied to the direct analysis of these analytes and other interfering chemicals including uric and ascorbic acids in urine samples without off-line sample treatment or preconcentration.
Zhou
Lin
L
Innovative Chromatography Group, Irish Separation Science Cluster (ISSC), Department of Chemistry & the ABCRF, University College Cork, Cork, Ireland.
Glennon
Jeremy D
JD
Luong
John H T
JH
D015415:Biomarkers / Q000652:urine*; D001895:Boron / Q000737:chemistry; D018130:Diamond / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D019075:Electrophoresis, Capillary / Q000379:methods; D005260:Female; D006046:Gold / Q000737:chemistry*; D006719:Homovanillic Acid / Q000302:isolation & purification / Q000652:urine; D006801:Humans; D007200:Indican / Q000302:isolation & purification / Q000652:urine; D053768:Metal Nanoparticles / Q000737:chemistry*; D011073:Polyamines / Q000737:chemistry; D000071228:Polyelectrolytes; D011095:Polyethylenes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D014642:Vanilmandelic Acid / Q000302:isolation & purification / Q000652:urine
D015415:Biomarkers; D001895:Boron; D018130:Diamond; D006046:Gold; D006719:Homovanillic Acid; D007200:Indican; D011073:Polyamines; D000071228:Polyelectrolytes; D011095:Polyethylenes; D000644:Quaternary Ammonium Compounds; D012822:Silicon Dioxide; D014642:Vanilmandelic Acid; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride