UNESCO Laboratory of Environmental Electrochemistry

2. UNESCO Laboratory of Environmental Electrochemistry Charles University in Prague Heyrovský Institute AS CR

3. BORON DOPED DIAMOND FILM ELECTRODES - AN EXCELENT TOOL FOR VOLTAMMETRIC MONITORING OF ENVIRONMENTALLY IMPORTANT ORGANIC SUBSTANCESJiri BarekUNESCO Laboratory of Environmental Electrochemistry, Department of Analytical Chemistry, Charles University,Prague, Czech Republic, e-mail: Barek@natur.cuni.cz

4. Why new electrode materials • Broader potential window • Lower noise and background current • Resistance toward passivation • Mechanical stability • Compatibility with „green analytical chemistry“

5. WHY BORON DOPED DIAMOND FILM ELECTRODES • Low noise • Broad potential windows • Low passivation • Mechanical and electrochemical stability • Biocompatibility • Comercial availability

6. Boron doped diamond film electrodes Properties of diamond • sp3 allotropic modification of carbon • Hardness • Low chemical reactivity • Insulant  doping by boron Properties of boron doped diamond • Low double layer capacity • Broad potential window • Low adsorption • Stability, biocompatibility

7. BDDFE

8. The potential window of BDD electrode, BR buffer pH 2 - 12

9. CVD - Chemical Vapor Deposition Radicals and other reactive species are formed in the mixture of methane and hydrogen. They diffuse to the surface of growing diamond layer. They react at the surface and deposits in the form of diamond. High hydrogen atom concentration prevents the formation of sp2 carbon species. Mechanism is not fully understood as yet Boron doping from solid (boron nitride) or gaseous (boranes,B2H6)sources

10. Boron doped diamond film electrode CVD - Chemical Vapor Deposition

12. BDDFE

14. Boron doped diamond film electrode (BDDFE) • Legend • Electrodebody • Screw contact • Screw attachment • Small metal spring • Brassy sheet • DFE on Si (1,1,1) • Silicone seal • Access for solution Surface of nanocrystalline diamond film electrode on Si

15. BDDFEGlass tube (1), copper wire (2), conductive epoxide resin (3), non-conductive epoxide resin (4), silica wafer covered with BDDF (5), diameter of BDDFE (d, 3 mm), surface of BDDFE (A, 7,1 mm2).

16. BDDFE Glass tube (1), copper wire (2), conductive epoxide resin (3), non-conductive epoxide resin (4), silica wafer covered with BDDF (5) Lab madeCommercial

17. Cyclic voltammogram of 2-nitrophenol at BDDE, BR buffer pH 3 E[mV]

18. 2-AB (a), 3-AB (b), and 4-AB (c) DPV at BDNDFE (2-10).10-7 M pH 7 pH 8 pH 9

19. DPV at BDDFE 10-5 M 1-nitropyrene 1-aminopyreneMeOH-BR pufr pH 3 (7:3) Regeneration E1 = +800 mV, t1 = 0,3 s E2 = -500 mV, t2 = 0,2 s

20. Pasivation1-AP (c = 1·10–4M)MeOH-BR pufr pH 3 (7:3) 11 measurements Potential span 0 až +1600 mV+230 až +680 mV ~ +440 mV

21. DPV at BDDFE of 4-NP (µM)in riverwater ReductionOxidation

22. DPV 1-AP at BDDFE (0- 10).10-6 M , MeOH-BR buffer pH 3,0 (7:3)

23. DPV 1-AP at BDDFE (0- 10).10-7 M , MeOH-BR buffer pH 3,0 (7:3)

24. BDDFE detector TL arrangement 1‑AN a 1‑AB(5.10-6M) DFE(a)a GCE(b)

25. Elektrochemical wall-jet detector with BDDFE WE Reference electrode Counter electrode

26. FIA-ED or HPLC-ED TL BDDFE Reference electrode Outlet Inlet Kel-f body, top piece rubber gasket working electrode metal backing - - current collector rubber backing Kel-f body, bottom piece screw clamp

27. BDDF microelectrodes

28. BDDF microelectrodes

29. HPLC-ED-BDDFE - 1-AP (0-10).10-7 M MeOH:0,05M PhB pH 5,0 (80:20), E = 1000 mV, v = 1,0 ml/min tR = 2,76 min

30. HPLC-ED-BDDFE - 1-HP (0-10).10-7 M MeOH:0,05M PhB pH 5,0 (80:20), E = 1000 mV, v = 0,8 ml/min tR = 3,93 min

31. HPLC-ED-BDDFE 1-AP in urine after SPE (0- 10).10-8 M MeOH:0,05 M PhB pH (80:20), E = 1000 mV, v =1,0 ml/min

32. HPLC-ED-BDDFE 1-HP in urine after SPE (0- 10).10-8 M MeOH:0,05 M PhB pH (80:20), E = 1000 mV, v =0,8 ml/min

33. Thank you for your attention