Current Density Probe

The Automated Scanning Electrode Technique system is designed to provide a robust, open platform for localized electrochemical research and development. ASET has been developed through a joint effort of Applicable Electronics, Inc. and Science Wares, Inc.

overview of ystem

close-up view


Localized 2D Total Current Density Probe

Signal detection down to nanovolts

Simultaneous measurement along 2 axes

Measurement times down to 0.02 seconds per point

Probe vibration covers 20x20 to 100x100 mm area

Probe size 10-50 mm


The Current Density Probe provides a non-invasive method for obtaining localized maps of total current density and ion specific gradients in aqueous media. Both probe data and video images are acquired to allow correlation of the data maps with the sample's visible features. Most datasets cover an plane area of anywhere from 100mm x 100mm to 5mm x 5mm with a 30x30 grid of measurement points. Acquiring such a dataset can take anywhere from 60 seconds to over an hour depending on the acquisition parameters at each measurement point in the scan. The measurement at each point involves moving a microprobe over a short path and recording changes in the probe signal relative to a reference electrode. The sample can be attached to an external control circuit such as a voltage clamp or potentiostat. Applications include corrosion research, surface quality analysis, toxicology studies, injury response measurement, growth and development studies, and ion concentration mapping.

system chematic


System Components

Model 200 Current Density Probe System
Differential Preamplifier x100 gain
Dual Oscillator/Driver with remote control
Dual In-Phase/Quadrature Lock-Ins
Manual Phase/Offset controls
Rear panel computer outputs
Plating and calibration current source
Frequency and voltage meter
Model 300 Ion Selective Probe System
Computer controlled sample and hold
DC coupled x1000 gain
Model CMC4 Computer Motion Control System
3 axis probe positioning stage
4 axis microstepping controller
Minimum incremental step down to 0.0031 mm
Top speed 2 mm/second
Model VZS1 Video Zoom Scope
7-45x continuous zoom magnification
Computer controlled focus
Fiber-optic ring illuminator
C-mount output, many modular options available
CCD video camera - B/W or color
510x492 pixel CCD, NTSCBRAL output
High-resolution and Color/RGB output available
B/W or Color Video Monitor for real time video
Unplated Pt-Ir or Stainless Steel Electrodes
10 per box, down to 2 or 5 mm exposed tips
Oscilloscope, Dual trace 20MHz
Optical bench and miscellaneous hardware
30"x36" magnetic surface
1/4x20 holes on 1" (or M6 on 25mm) centers
Data Acquisition Software
Windows 95, Windows 3.11, or DOS compatible
Point source, Nernst, Polarographic Calibrations
Strip-chart type watch modes
3-D programmable grid and vector scans

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Localized 3D Ion Selective Gradients


LIX based [Ca++], [H+], [K+]

Voltage gradients down to 10 nV

Measurement times down to 0.25 seconds per point

Programmable probe path covers as little as 5 mm

Probe tip size down to 1 mm

proton microvolt data Scan of two proton sources using a 7x22 grid with 80 mm steps. The exported dVx, dVy, dVz proton microvolt data is displayed as vectors using PCMage version 4.2. This data was collected at the University of Massachusetts Vibrating Probe Facility (UMASS-VPF):

http://www.bio.umass.edu/biology/kunkel/nvp_umass.htm
Shown courtesy of Dr. Joe Kunkle, PhD, Department of Biology (joe@bio.umass.edu).

Both probe data and video images are acquired to allow correlation of the data maps with the sample's visible features. Most datasets cover an plane area of anywhere from 100mm x 100mm to 5mm x 5mm with a 30x30 grid of measurement points. Acquiring such a dataset can take anywhere from 60 seconds to over an hour depending on the acquisition parameters at each measurement point in the scan. The measurement at each point involves moving a microprobe over a short path and recording changes in the probe signal relative to a reference electrode. The sample can be attached to an external control circuit such as a voltage clamp or potentiostat. Applications include corrosion research, surface quality analysis, toxicology studies, injury response measurement, growth and development studies, and ion concentration mapping.


Other Scanning Probe applications


Multiple barrel electrodes

Localized impedance measurements

Polarographic probes (dissolved oxygen)

Voltammetric probes (cyclic and stripping voltammetry)



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Maintained by Anastasia Karplus
email: sia@sciencewares.com
last updated 10/2/2003
Copyright © 2003 Science Wares, Inc., all rights reserved.