Introduction - Determination of Anions in Natural and Treated Waters - page 23

electrode functions could only be set and adjusted for a single substance even automatic
range switching of the recorder was of very little use.
The dilemma is solved with the 646 VA processor: the freedom to divide the voltage
sweep into substance-specific segments and to adjust all conditions individually and
independently of one and another within these segments opens up quite a new and, to
date, unknown analytical possibility. Furthermore, it allows optimum evaluation of the
experimental data.
Various suppliers of polarographs are summarised in Table 1.5.

Table 1.5 Suppliers of polarographs

Supplier Type Model No. Detection

limits

2-10 µg L −1
quoted for
nitriloacetate

Metrohm Differential

pulse
Direct current
Square wave

646 VA processor
647 VA stand
675 VA sample
changer
665 Dosimat (motor
driven piston burettes
for standard
additions)

Direct current normal pulse differential
pulse 1st harmonic ac. 2nd harmonic ac.
Kalousek

506 Polarecord

Direct current sampled differential pulse DC 626 Polarecord

~0.1µg L −1

Chemtronics
Ltd

On-line voltammetric analyser for metals
in effluents and field work

PDV 2000

RDT
Analytical
Ltd

Differential pulse anodic stripping on-line
voltammetric analyser for metals in
effluents and field work

ECP 100 plus
ECP 1 04
programmes
ECP 140
PDV 200

On-line voltametric analyser for
continuous measurement of metals in
effluents and water

OVA 2000

EDT
Analytical
Ltd

Cyclic voltammetry differential pulse
voltammetry linear scan voltammetry,
square-wave voltammetry, single- and
double-step chronopotentiometry and
chronocoulometry

Cipress Model
CYSY-1B (basic
system) CY57-IH-
(high-sensitivity
system)

Source: Own files