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

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Presentation on theme: "UNESCO Laboratory of Environmental Electrochemistry Charles University in Prague Heyrovský Institute AS CR."— Presentation transcript:

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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 SUBSTANCES Jiri Barek UNESCO Laboratory of Environmental Electrochemistry, Department of Analytical Chemistry, Charles University, Prague, Czech Republic,

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 Properties of diamond sp 3 allotropic modification of carbon Hardness Low chemical reactivity Insulant  doping by boron Low double layer capacity Broad potential window Low adsorption Stability, biocompatibility Properties of boron doped diamond Boron doped diamond film electrodes

7 BDDFE

8 The potential window of BDD electrode, BR buffer pH

9 CVD - Chemical Vapor Deposition Mechanism is not fully understood as yet 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 sp 2 carbon species. Boron doping from solid (boron nitride) or gaseous (boranes,B 2 H 6 ) sources

10 CVD - Chemical Vapor Deposition Boron doped diamond film electrode

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12 BDDFE

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14 Boron doped diamond film electrode (BDDFE) Legend 1.Electrode body 2.Screw contact 3.Screw attachment 4.Small metal spring 5.Brassy sheet 6.DFE on Si (1,1,1) 7.Silicone seal 8.Access for solution Surface of nanocrystalline diamond film electrode on Si

15 BDDFE Glass 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 mm 2 ).

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

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) M pH 7 pH 8 pH 9

19 DPV at BDDFE M 1-nitropyrene 1-aminopyrene MeOH-BR pufr pH 3 (7:3) Regeneration E 1 = +800 mV, t 1 = 0,3 s E 2 = -500 mV, t 2 = 0,2 s

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

21 DPV at BDDFE of 4-NP (µM) in river water Reduction Oxidation

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

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

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

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

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

27 BDDF microelectrodes

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

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

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

33 Acknowledgement This research was supported by the Ministry of Education, Youth and Sports of the Czech Republic (projects LC and MSM )

34 Thank you for your attention

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