there's been quite a lot of recent
discussion about chemical weapons so we
thought it might be useful for you to
know a bit about their chemistry so that
you can understand the discussions
rather
better so I know a little bit about some
of these things in particular nerve
gases just because some of the research
I do looks at the nervous system and how
we can interact with it uh actually to
control pain rather than kill anyone use
of chemical weapons really began in the
first world war first of all they Ed
chlorine which is a sort of yellowish
gas so you could see it coming across
the battlefields you had trench warfare
these would go along no man's land down
into the trenches and obviously Ma and
kill um the the enemy or if you got the
wind direction wrong your own troops
mustard gas which is chemical weapon
which was used again in the Iraq Iran
War in the
1980s is although it's called a gas it
is actually liquid which made it
particularly unpleasant because it would
persist on the battlefield for months
mustard gas that was shot in the Autumn
could still be there in the spring and
affect people and it caused
blindness for those people who were not
actually killed by it but the rather
maab twist to the chemistry of mustard
gas is that
it has since been used or derivatives of
it have been used in medicine and more
people have been saved by derivatives of
mustard than were killed in the various
uses on the battlefield run up and in
particular in the early stages of the
second World War I guess both sides
allies and and the Nazis they were both
developing more sophisticated chemical
warfare agents presumably in case the
other side us it uh luckily um although
the lots of developments were made um
luckily there was no chemical warfare
whatsoever in the second world war and
uh none of these uh items got used but
nonetheless the technology had been
developed um and so these days the you
know there there is some knowledge out
there about these more advanced systems
of which sarin is one of them
unfortunately terrorists can get hold of
it I've got a molecule of s in here here
not real siren uh not real siren no that
would be uh illegal to make that I've
made it out of uh straws and uh these
colored balls here quite a small
molecule uh not many atoms and that's
why it's volatile it's a gas or a very
low boiling liquid here we have a
phosphorus this purple one these two red
ones are oxygen the black ones are
carbon and the thing which makes it the
reactive um and volatile to some extent
is this one here this is a Florine and
what this does is it blocks something in
all animals uh humans um called atile
choline esteras that's the what it works
on there was great worry in the UK that
chemical weapons which by the time of
the second world war were much more
sophisticated um might be used so all um
British citizens even babies were given
respirators or gas
masks and I've got my
father's gas mask I think they were
presented in a cardboard box but my
father had this rather Posh leather case
made for it and if you look inside it
has his name he's written a poov
Esquire and he's got his the his work
address and even his telephone number
inside is the gas mask itself I haven't
taken it out for many years and I think
it might be perished but let's see if we
can get it out so what is atile choline
esterase well before I tell you what the
esterase bit means I'll tell you a bit
about acety Chine so this is a molecule
here of atile choline and this is a
neurotransmitter so whenever we breathe
or move our arms or do a whole range of
things heartbeats and whatnot um we use
our nervous system and our brain sends a
signal now throughout most of it is like
an electrical cable but when it gets to
a junction those signals are are
transferred by neurotransmitters and
acetycholine is one type of
neurotransmitter so this drifts across
the Coptic Gap The
Junction and it triggers the next
response and that response might be the
arm moves or lungs breathe I think I may
need to stand up for this so here are
the straps but let's see what's left
inside when you want that response to
die off what happens is this drifts away
from its receptor and a molecule like a
pacman comes along and chews this up and
that molecule is called acety choline
estate so that's the totally natural
very good thing very good thing because
otherwise if you move your arm it would
always be there you wouldn't be able to
stop it and get it back and again
breathing you'd be always breathing out
and not breathing
in there's something
coming so here we
are this is now completely come
off and there is an eye
piece and the thing that you breathe
through so you need this to go on and
this happens you know in milliseconds
it's incredibly quick incredibly quick
and all that happens is the this acetal
colian estr comes along and it takes
that end
off this is now vinegar over here and
the other bit is choline and that gets
recycled to make more acety choline in
the receptor end well you can't see very
much it's a bit dirty I can just about
see the camera I couldn't drive in this
and and what it would have been like
walking in the complete darkness of
blackouts I have no idea so that process
is going on on and on and on constantly
in our bodies and what sarin does is it
comes
along and the molecule which which takes
this end group off here let's let's call
it
this uh thing here it's this o which is
going to happen that's the Pacman is it
that's the the Pac-Man molecule comes
along it swaps that for that and then
water comes in and takes this off to
make acetic acid
well sarin comes along and it's got a
much more active group The Florine is
really reactive that
goes and this attaches
on but now water can't take this off
again so it's just soaked up one of
these Pacman molecules acine estr
molecules well now you see it's not
available to break down the acetycholine
in your body so you've always got an on
switch on your muscles and the thing
which is deadly is is you're breathing
because obviously your lungs and muscles
they move in and out and if they don't
go one way and don't go back the other
way then you know you you're very
quickly die of Suffocation which is why
you see uh in all these news reports
people with you know really bad
breathing problems and it's because they
they can't get those muscles to work
correctly because the acetycholine raay
has been mopped up by the
sarin and the water can't hydrolize
inside
here will be activated carbon charcoal
which has a very large surface area and
will absorb the molecules of the poison
gas and I believe though I'm not certain
that they found that
coconut charcoal was by far the best one
I from coconut I don't know it just
probably gave a higher surface area so
there is an antidote and of course
whenever chemists have designed in the
past poisonous things obviously they
don't want to kill themselves they're
clever guys they they invent some sort
of antidote and the antidote is this
molecule it's called pral
doxine and this is like super water so
here's an oxygen here and it's connected
to this nitrogen and that makes this
oxygen about 100 to 300 times more
reactive than normal water and that can
come along and displace the sarin from
the asalan estray and that can go about
its business again now the other thing
which is perhaps more interesting is
this which I bought as a school boy in
the early
1960s as far as I remember I paid 5
Shillings for it 25 UK
Pence and and 60 at that time 60 us
cents so not very much inside if you
look this is a kit a military kit for
detecting poisonous gases and here the
instructions how to use it here there's
a whole Lab of little different vessels
and
underneath is
essentially what is a bicycle
pump except instead of pumping things up
it sucks air through a hole at the top
you put the chemical tester here and
then you pump like this and it sucks air
through so you've got to imagine me now
wearing a gas mask and gloves because
there may be chemical it was that you
put the thing in here and then out of
here you took a small paper disc so
imagine wearing gloves and with the
battle raging around me and and you put
a chemical this piece of filter paper in
here and then you start mixing up
Solutions here and start pumping away
and see if you get a color does this
stuff scare you totally absolutely yeah
yeah I mean it's it's horrendous the the
lethal dose for this is around 1 mgram
Far smaller than the smallest sort of uh
sweetener pill that you might put in
your coffee for example we think of
cyanide sodium cyanide is being quite
dangerous but you'd need sort half a
teaspoonful of of that so you can see
that these These are you know around
thousand times more deadly than than
even Cyanide and we all know that that
was uh horrendous I think one of the
problems of chemical weapons is that
they are not targeted at particular
individuals in the way that you would if
you shoot a gun at them you can't
control them I mean if you're aiming a
bomb or a missile at a building you're
you're aiming at that building but if
you
release gas it's going to go over the
wind blows it and there's no control of
who's in the way and who isn't also that
the members of society who are most
vulnerable old people young children are
those that are likely to suffer most
from chemical weapons because if you
know their chemical weapons about and
you're properly equipped such as
soldiers with all their Battlefield kit
then they're relatively little danger
you cannot easily protect yourself from
exploding bombs if they're big ones but
you can from chemical weapons so part of
the revulsion I think that everyone
feels about chemical weapons is that
they're not targeted individuals and
innocent bystanders can so easily
be injured or
killed so look at the the blue one the
nitrogen this is a cat tet trimethyl
ammonium species there is a huge problem
now that there are aging stock pales in
various places of chemical weapons that
need to be destroyed