title: Pattern recognition of neurotransmitters using multimode sensing.
abstract: BACKGROUND
  Pattern recognition is essential in chemical analysis of biological fluids. Reliable and sensitive methods for neurotransmitters analysis are needed.
  
  
  METHODS
  Therefore, we developed for pattern recognition of neurotransmitters: dopamine, epinephrine, norepinephrine a method based on multimode sensing. Multimode sensing was performed using microsensors based on diamond paste modified with 5,10,15,20-tetraphenyl-21H,23H-porphyrine, hemin and protoporphyrin IX in stochastic and differential pulse voltammetry modes.
  
  
  RESULTS
  Optimized working conditions: phosphate buffer solution of pH 3.01 and KCl 0.1mol/L (as electrolyte support), were determined using cyclic voltammetry and used in all measurements. The lowest limits of quantification were: 10(-10)mol/L for dopamine and epinephrine, and 10(-11)mol/L for norepinephrine. The multimode microsensors were selective over ascorbic and uric acids and the method facilitated reliable assay of neurotransmitters in urine samples, and therefore, the pattern recognition showed high reliability (RSD<1% for more than 6 months) for the simultaneous determination of dopamine, epinephrine and norepinephrine from urine and whole blood samples.
  
  
  CONCLUSIONS
  The proposed method can perform pattern recognition of the three neurotransmitters on biological fluids at a lower determination level than chromatographic methods. The sampling of the biological fluids referees only to the buffering (1:1, v/v) with a phosphate buffer pH 3.01, while for chromatographic methods the sampling is laborious.
  
  
  CONCLUSIONS
  Accordingly with the statistic evaluation of the results at 99.00% confidence level, both modes can be used for pattern recognition and quantification of neurotransmitters with high reliability. The best multimode microsensor was the one based on diamond paste modified with protoporphyrin IX.
authors.affiliation: Laboratory of Electrochemistry and PATLAB Bucharest, National Institute of Research for Electrochemistry and Condensed Matter, Splaiul Independentei No. 202, Bucharest, Romania; Faculty of Applied Chemistry and Material Science, Politehnica University of Bucharest, Bucharest, Romania. Electronic address: iustinavanstaden@yahoo.com.
authors.forename: Raluca-Ioana
authors.initials: RI
authors.lastname: Stefan-van Staden
authors.affiliation: Laboratory of Electrochemistry and PATLAB Bucharest, National Institute of Research for Electrochemistry and Condensed Matter, Splaiul Independentei No. 202, Bucharest, Romania; Faculty of Applied Chemistry and Material Science, Politehnica University of Bucharest, Bucharest, Romania.
authors.forename: Iuliana
authors.initials: I
authors.lastname: Moldoveanu
authors.affiliation: Laboratory of Electrochemistry and PATLAB Bucharest, National Institute of Research for Electrochemistry and Condensed Matter, Splaiul Independentei No. 202, Bucharest, Romania.
authors.forename: Jacobus Frederick
authors.initials: JF
authors.lastname: van Staden
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D001774:Blood Chemical Analysis / Q000379:methods; D018130:Diamond; D004298:Dopamine / Q000032:analysis*; D004837:Epinephrine / Q000032:analysis*; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods*; D018625:Microscopy, Atomic Force; D018377:Neurotransmitter Agents / Q000032:analysis; D009638:Norepinephrine / Q000032:analysis*; D010363:Pattern Recognition, Automated / Q000379:methods*; D012680:Sensitivity and Specificity; D013269:Stochastic Processes; D014556:Urine / Q000737:chemistry
chemical_list: D018377:Neurotransmitter Agents; D018130:Diamond; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine
keywords: Diamond paste, Multimode sensing; Neurotransmitters, Pattern recognition