Chemistry Reference
In-Depth Information
Chapter 16
On-site measurement of anions
This chapter discusses available portable instrumentation that can be carried around by
inspectors to carry out measurements for anions on rivers, reservoirs, effluents, etc.
Merck supply a range of test kits covering many different determinands (Table 16.1).
Test strips and test kits, both visual and photometric are available and all are suitable for
use in the field.
Merckoquant Test Strips
These consist of a reactive test zone firmly bonded to a plastic backing. The test zone is
impregnated with reagents, buffers and other substances. The strips are used for rapid
exploratory testing of substance concentrations as low as 1mg L
−1
. To test a sample the
test zone is immersed in the water sample for 1-2s and matched against a colour scale.
Aquamerck Test Kits
These consist of titrimetric and colorimetric test kits supplied in boxes or blister packs.
The simplest titration tests contain a dropping bottle or precision dropping pipette. The
number of drops of reagent required to change the colour of the indicator is a measure of
the concentration of the substance being tested for. Aquamerck colorimetric tests
incorporate a waterproof scale with precise directions, or alternatively a testing vessel
consisting of a 10mm cell with coloured reference blocks to the right and left of it so that
a colour comparison can be made.
Aquaquant Test Kits
The aquaquant system for rapid water analysis fully meets the stringent requirements
relating to detection sensitivities, ease of use and economy. Each Aquaquant test kit
consists of a plastic case containing a sliding colour comparator, which is of a moulded
construction designed to hold
Table 16.1
Test kits supplied by Merck
Determination
Measuring
range
graduation
mg L
−1
Merckoquant
test strips
Aquamerck
titrimetric
test with
dropping
Aquamerck
colorimetric
test in a
blister pack
Aquamerck
colorimetric
test with
colour scale
Aquam
colorim
test
te
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