Proceedings of the International Cyanide Detection Testing Workshop

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cyanide hydratase converts the toxic
cyanide into non-toxic products for
measurement
the combination of enzymes makes
the system highly specifi c
there is no need for vigorous sample
pre-treatment
no use of hazardous chemicals
To take this work a step further, Mak et al.
(Mak, Yanase et al., 2005) used the microbial
sensor system to measure cyanide levels in
marine fi sh. They exposed fi sh to sub-lethal
doses of 10 μM potassium cyanide in seawater
for 15 minutes and then transferred the fi sh
to clean seawater for recovery. After different
recovery times (0-180 minutes), fi sh were
tested for residual cyanide using the biosensor
system. Results are expected in a forthcoming
publication (Mak et al., in prep).
Cyanide Testing Protocols Used in Non-
Fish Settings
Because of the fact that cyanide is a toxic poison
and the fact that it can be an environmental
pollutant, there is a large scientifi c literature
on cyanide detection.
Table 1 summarizes the most common
cyanide detection tests as well as advantages
and disadvantages of each test. Table 2
presents a sampling of cyanide detection tests
in human, fi sh, and mouse blood, urine, and
tissue samples. In addition, Table 2 presents
some publications reporting on a variety of
cyanide detection tests.
It is interesting to note that there is a large
amount of activity in the U.S. federal
government to develop rapid cyanide
detection in humans in order to prepare for
a potential bioterrorist attack using cyanide.
It is possible to explore these methods and
experts to fi nd avenues through which to
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improve the current cyanide detection system
for marine fi sh.
The current method used to test cyanide
concentrations in fish employs the Ion
Selective Electrode (ISE) methodology. This
method is not highly sensitive and it is subject
to a tremendous amount of interference
with samples found in seawater. Tables 1 and
3 present a wide range of methodologies,
each with varying degrees of cost, sensitivity,
and potential effectiveness for marine fi sh
samples.
Because cyanide breaks down so quickly in
fi sh, it may be necessary to develop a test
that measures a by-product of cyanide. Some
of the possibilities to explore in this arena
include:
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Thiocyanate. Thiocyanate is a
non-toxic by-product of cyanide
degradation.
Other biological by-products such as:
o formate (Mak, Law et al.,
2005)
o a cyanide/hemoglobin adduct
(Kobeleski, pers. com.)
o2-aminothiazoline-4- carboxylic acid (ATCA)
(Logue, Kirschten et al.,
2005)
o a gill protein that is changed
upon cyanide exposure (Chu,
Liu et al., 2001)
Cytochrome oxidase — dose-related
reductions in cytochrome c oxidase
activity were detected in various
organs of rats exposed to oral doses
of potassium cyanide (Ikegaya,
Iwase et al., 2001). This marker was
suggested as a method of diagnosis
for samples taken within two days
post-mortem.