The TE 4000 is an easy to
use, computer operated electrochemical system for polarography,
voltammetry and Amperometry. The unit is very
compact and can easily be used in the field in conjuction with a
laptop PC via the USB interface.
The sensitivity of the instrument is comparable with AAS and in many cases it is even better. The system is delivered with a 100 plus page booklet of methods.
Polarography is a technique in which an electric potential (or voltage) is varied in a regular manner between two or three electrodes (working, reference, and auxiliary) while the current is monitored. The working electrode can be solid (gold, platinum or glassy carbon) or formed by a drop of mercury hanging from a tip of a capillary. If the electrode is formed by a drop of mercury rhythmically dropping from a capillary, the analytical technique is called Polarography. At a specific potential oxidation or reduction of the analyte occurs, which causes an increase of the current which depends on the concentration of the analyte. The shape of a polarogram depends on the method of analysis selected, the type of working electrode used, and the potential ramp that is applied.
Most common techniques are DC (Direct Current, linear sweep) and DP (Differential Pulse, linear
sweep with pulses superimposed). Classical polarography uses a dropping mercury electrode, which causes a high consumption of mercury. Modern Instruments such as the TEA 4000 work with a hanging mercury drop, which minimizes the mercury consumption, and enables “Stripping Voltammetry”.
Stripping voltammetry means, that the analyte is ccumulated in a first step at the surface of the
working electrode. To do so an appropriate accumulation potential is applied to the electrode for a
defined time intervall (accumulation time). The analyte is then stripped back into the solution in a
second step. The enrichment of the analyte effects the high sensitivity.
The most sensitive methods are anodic, cathodic and adsorptive stripping voltammetry, combined with the differential pulse technique. The detection limits using stripping voltammetry depends on the analyte, the best detection limits are about 0,01 μg/l (ppb).
TheT 4000 polarography / voltammetry system is suitable for use in the laboratory or on site in many fields of application including: water analysis of natural, waste and fresh water; food and beverage, sanitation, environmental analysis, pharmaceutical, chemical, oil and plating industries, medicine, biology, geology and tribometry. The instrumentation is supplied with a comprehensive manual of analytical methods.
|The example above shows the simultaneous determination of Zn , Cd, Pb and Cu using standard addition|
|Al||3 ppb||Cu||0.05 ppb||Pb||0.05 ppb||Zn||0.05 ppb||As||0.1 ppb||Fe3+||0.03 ppm||Cl||1 ppb|
|Ag||1 ppb||Hg||0.03 ppb||Mo||0.05 ppb||As3+||0.1 ppb||Mn||0.5 ppb||NO3-||0.05 ppm||PO4 2-||20 ppm|
|Cd||0.05 ppb||Cr4+||0.01 ppb||Pd||0.01 ppb||Co||0.01 ppb||Fe||0.03 ppm||NO2-||0.01 ppm||SO4 2-||20 ppb|
|Cr||0.01 ppb||Ni||0.01 ppb||Se||1 ppb||Ti||0.05 ppb||Be||0.1 ppb||NH4+||60 ppm||S2-||0.01 ppm|
|Model||Description||Part No||Price USD|
|TEA 4000 SET||
System with USB and software.
Polarography Standards Cd, Hg Zn Pb, Cu, As, Ni, Ti,Tl, Cr(total) Cr(Vl), Co, Ag, Sn, Fe, Mn, Sn, Se and Al.
|HMDE ( hanging mercury drop electrode )||4000HMDE|
|Glassy carbon electrode||4000GCE|
|Electro magnetic valve||4000EMV|
|Reference Ag/AgCl electrode||4000AG|