
77-11Air Pollution Monitoring
Many of the manufacturers listed in Table 77.2 supply direct-throughput FIDs for ambient. ermo-
Scientic oers an instrument (55i) which combines a FID with a cycled gas chromatograph, thereby
be
tter
gu
aranteeing
se
paration
be
tween
me
thane
an
d
NM
HC,
th
ough
at th
e
co
st
of a lo
nger
cy
cle
ti
me
.
e Ph
otovac
ra
nge
of in
struments,
no
w
su
pplied
by In
con,
in
cludes
a ha
ndheld
FI
D
(M
icroFID),
wh
ich
is de
signed
to be in
trinsically
sa
fe
an
d
in
tended
fo
r,
e.g., wo
rkplace
mo
nitoring
or le
ak
de
tection
.
As s
uch
i
t
i
s
e
xtremely
f
ast:
<
3
s to 9
0%
r
esponse
.
An alternative technique for hydrocarbons is PID. is is nonspecic, wit