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1 of 10 Pulsed Voltammetric Techniques Typical Set up for Polarography Pulsed Voltammetric Methods
10

Pulsed Voltammetric Techniques

Feb 04, 2016

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Pulsed Voltammetric Methods. Pulsed Voltammetric Techniques. Typical Set up for Polarography. Pulsed Voltammetric Methods. DC Polarography with Dropping Mercury Electrode (DME). Pulsed Voltammetric Methods. Sample-and-Hold or Tast (sampled-current) Voltammetry. D E. E. t. t. - PowerPoint PPT Presentation
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Page 1: Pulsed Voltammetric Techniques

1 of 10

Pulsed Voltammetric Techniques

Typical Set up for Polarography

Pulsed Voltammetric Methods

Page 2: Pulsed Voltammetric Techniques

2 of 10

DC Polarography with Dropping Mercury Electrode (DME)

Pulsed Voltammetric Methods

Page 3: Pulsed Voltammetric Techniques

3 of 10

Sample-and-Hold or Tast (sampled-current) Voltammetry

Pulsed Voltammetric Methods

E

t

E

6/13/2*2/1708)( mCnDi OOd

3/13/2 )(00567.0)( EEmCi PZCid

Current is sampled late in the drop life, so faradaic current is minimized versus near onset.

LOD ~ 10-5 M

Page 4: Pulsed Voltammetric Techniques

4 of 10Normal Pulse (NPV or NPP) vs. Tast Voltammetry

Pulsed Voltammetric Methods

Current sampled and held.

2/12/1

*2/1

)'()(

OO

NPVdCnFADi

' If > 5RsCd (~0.05-15 ms), icharging is almost insignificant. LOD ~ 10-5 -10-6M

Page 5: Pulsed Voltammetric Techniques

5 of 10

Page 6: Pulsed Voltammetric Techniques

6 of 10

DPV

NPV

Differential Pulse (DPV) vs. Normal Pulse VoltammetryPulsed Voltammetric Methods

Small ifaradaic

when away from E0’

Large ifaradaic when near E0’

LOD ~ 10-6 -10-7 M

Page 7: Pulsed Voltammetric Techniques

7 of 10

NPV

DPV

OsteryoungSquareWaveVoltammetry

Comparison of Excitation Waveforms for Pulsed VoltammetriesPulsed Voltammetric Methods

Page 8: Pulsed Voltammetric Techniques

8 of 10Osteryoung Square Wave Voltammetry Pulsed Voltammetric Methods

LOD ~ 10-8 M

Page 9: Pulsed Voltammetric Techniques

9 of 10Osteryoung Square Wave Voltammetry

Pulsed Voltammetric Methods

Page 10: Pulsed Voltammetric Techniques

10 of 10

Stripping Analysis Coupled to DPV - DPASV

ip = 0.138 Qmetal/tpulse-width

~50-nm thick Hg film on Glassy Carbon (vitreous) electrode by electrodeposition from acidic Hg2+

DPVDeposit M0

Limit of Detection of ~0.005 ppm

Pulsed Voltammetric Methods