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Pulsed Voltammetric Methods
Pulsed Voltammetric Techniques
Typical Set up for Polarography
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Pulsed Voltammetric Methods
DC Polarography with Dropping Mercury Electrode
(DME)
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Pulsed Voltammetric Methods
Sample-and-Hold or Tast (sampled-current)
Voltammetry
DE
E
t
t
Current is sampled late in the drop life, so
faradaic current is minimized versus near
onset. LOD 10-5 M
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Pulsed Voltammetric Methods
Normal Pulse (NPV or NPP) vs. Tast Voltammetry
Current sampled and held.
If gt 5RsCd (0.05-15 ms), icharging is
almost insignificant.
LOD 10-5 -10-6M
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Pulsed Voltammetric Methods
Differential Pulse (DPV) vs. Normal Pulse
Voltammetry
NPV
DPV
Large ifaradaic when near E0
Small ifaradaic when away from E0
LOD 10-6 -10-7 M
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Pulsed Voltammetric Methods
Comparison of Excitation Waveforms for Pulsed
Voltammetries
NPV
DPV
Osteryoung Square Wave Voltammetry
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Osteryoung Square Wave Voltammetry
Pulsed Voltammetric Methods
LOD 10-8 M
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Pulsed Voltammetric Methods
Osteryoung Square Wave Voltammetry
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Stripping Analysis Coupled to DPV - DPASV
Pulsed Voltammetric Methods
ip 0.138 Qmetal/tpulse-width
50-nm thick Hg film on Glassy Carbon (vitreous)
electrode by electrodeposition from acidic Hg2
DPV
Deposit M0
Limit of Detection of 0.005 ppm