SENSOLYTICS Microelectrodes MICROELECTRODES

All microelectrodes offered by Sensolytics have a similar design. The electrode material is isolated by a glass sheath which forms the electrode body. Electrical connection is achieved by a copper wire. All electrodes are disk-shaped with a sharp tip.

85 mm

1,5 mm

Figure 1: Photograph and scheme of a microelectrode For quality assurance, all microelectrodes are tested by cyclic voltammetry. A typical voltammogramm is shown in figure 2.

2

i/nA

0

-2

-4

-6

For a rough calculation, a cyclic voltammogramm in

-8

a 5 mM solution of rutheniumhexamin or ferricya-

-10

nide can be used. The diffusion controlled current E/mV vs.Ag|AgCl (3 M KCI) it,∞ in nA corresponds to the diameter in µm.

-12

-500

-400

-300

-200

-100

0

100

Figure 2: Cyclic voltammogram of a 10 µm Pt-microelectrode in 5 mM Ru(NH

3+

3)6

/100 mM KCl solution



GOLD MICROELECTRODES

Gold disk microelectrodes are available in three different diameters. The gold core is sealed in soda glass with an outer diameter of 1 mm. They are especially suitable for thiol modifications.

PLATINUM MICROELECTRODES

Microelectrodes with platinum as the electroactive electrode material are the most chosen electrodes for SECM

measurements. The insulating sheath of the platinum microelectrodes consists of borosilicate glass. They are suitable for a wide range of applications because of their wide potential window and chemical inertness. For standard SECM

applications, it is recommend to use electrodes with a diameter of 25 µm or 10 µm.

PLATINUM NANOELECTRODES

Platinum nanoelectrodes are used for imaging in constant-distance mode SECM. The electrodes consist of a quarz-glass sheath which is pulled into a needle shaped form. The diameter of the active electrode surface varies from 200

to 500 nm. The needle-type shape of the electrode is set to vibrate during the measuring process. In order to keep the distance between electrode and sample surface constant, a shear-force based distance control is used.

Figure 3: Photograph of a platinum nanoelectrode Sensolytics offers different types of electrodes with several electrode materials and diameters which are listed below.

Order No.

Name

04-00001

reference electrode Ag/AgCl 04-00002

counter electrode, platinum 04-00003

microelectrode, gold 10 µm 04-00004

microelectrode, gold 25 µm 04-00005

microelectrode, gold 50 µm 04-00006

nanoelectrode, platinum 200-500 nm 04-00007

microelectrode, platinum 10 µm 04-00008

microelectrode, platinum 25 µm 04-00009

microelectrode, platinum 50 µm 04-00010

microelectrode, platinum 100 µm Feel free to ask for non-listed products...

Universitätsstraße 142

Tel. +49 (0) 234 - 708 90 95

info@sensolytics.de

D-44799 Bochum

Fax +49 (0) 234 - 708 90 97

www.sensolytics.de