Pulsed Voltammetric Techniques
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1 of 10 Pulsed Voltammetric Techniques Typical Set up for Polarography Pulsed Voltammetric Methods
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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
Transcript of Pulsed Voltammetric Techniques
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Pulsed Voltammetric Techniques
Typical Set up for Polarography
Pulsed Voltammetric Methods
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DC Polarography with Dropping Mercury Electrode (DME)
Pulsed Voltammetric Methods
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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
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
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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
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NPV
DPV
OsteryoungSquareWaveVoltammetry
Comparison of Excitation Waveforms for Pulsed VoltammetriesPulsed Voltammetric Methods
8 of 10Osteryoung Square Wave Voltammetry Pulsed Voltammetric Methods
LOD ~ 10-8 M
9 of 10Osteryoung Square Wave Voltammetry
Pulsed Voltammetric Methods
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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
