• 10 •
800-356-1688 •
2004vol. 3
ConvenientCalibration,FasterGC/MS
Analysis forVolatileOrganics inWater
Using aNewRestek CalibrationMix and an Rtx
®
-VMS Column
Volatile organic analytes (VOAs) are a common
source of environmental pollution, and are
among themost difficult and expensive contami-
nants tomonitor inwater. Analysis and quantifi-
cation of VOAs in drinkingwater are detailed in
US EPAmethods 502 and 524, and inmany other
methodsworldwide.
Until now, Restek has offered two complex cali-
brationmixes of volatile compounds for drinking
water analysis: amix containing 54 target com-
pounds (502.2MegaMix
™
, cat.# 30432), and one
containing 73 compounds (DrinkingWater VOA
MegaMix
™
524.2 Rev. 4.2, cat.# 30601).The only
target compounds in the EPAmethods that we
do not include in thesemixes are the highly
volatile gases, and, forMethod 524.2, the reac-
tive ketones.To prevent acetal formation, we
offer the five ketones as a separatemix (cat.#
30602).We also offer the six gases separately,
as 502.2 CalibrationMix#1 (cat.# 30042 or
cat.# 30439). Analystsmonitoring samples for
the gases combine the gasesmixwith either the
54-component mix or the 73-component mix—
this takes time and can introduce variation or
mixing errors.
For the convenience of our customers, we have
developed a new 60-component calibrationmix
(VolatilesMegaMix
™
withGases, cat.# 30603)
that contains the 54 target compounds in 502.2
MegaMix
™
mix, plus the six gases in 502.2
CalibrationMix#1, at 200 ppm each in purge
and trapmethanol.The newmix is suitable for
Method 502, Method 524, or othermethods fol-
lowed inmonitoring these compounds.
The newmix brings a choice.The 60-component
mix is very convenient to use, and eliminates
both variation and the potential for errors
(associatedwithmeasuring andmixing from
multiple ampuls). An unopened ampul of thismix
has a 24-month shelf life, but once the ampul is
opened, the gases can begin to escape from the
solution, and opened ampuls of the newmix
should be replacedmore frequently than ampuls
of the 54-component mix. (This also is true of
the 6-component gasmix.) Analysts choosing to
workwith the 54-component mix and the six
gasesmixmust contendwith the potential for
mixing errors, but can see longer lifetimes from
ampuls of the opened 54-component mix—if
they are stored properly.We recommend storing
all VOAs referencemixes in a freezer, especially
those containing the gases.
Chemistsmonitoring VOAs inwater require fast
and accurate analyses. A chromatography col-
umnwith a cyanopropylphenyl/dimethyl poly-
siloxane stationary phase (e.g., a “624” column)
or a diphenyl/dimethyl polysiloxane phase (e.g.,
a “502.2” column) can provide a fast analysis,
but some compounds are likely to coelute, creat-
ing quantification problems. In contrast, Rtx
®
-
VMS columns are designed specifically for
analyses of volatiles by GC/MS, and circumvent
such problems. Analysis on a 20m, 0.18mm ID,
1.0µmRtx
®
-VMS column (cat.# 49914), using a
45ºC initial oven temperature, will provide good
resolution of the early eluting gases and ensure
faster oven cycles. Under optimized analytical
conditions and using a dual purge and trap sys-
tem, as shown in Reference 1, Figure 47, the
narrow bore column can reduce the analysis
time to approximately 10minutes, without sacri-
ficing resolution.
If you are testing for volatiles in drinkingwater,
wastewater, or hazardouswaste, an Rtx
®
-VMS
column and our new 60-component volatiles
MegaMix
™
with gaseswill help youmeet the
requirements formost analytical methods.
Reference
1.
Optimizing the Analysis of
VolatileOrganic Compounds
Restek technical guide,
lit. cat.# 59887A,
free on request.
Also available on our website.
by KatiaMay, Ph.D., Senior R&DChemist, and Jack Crissman, Ph.D., Analytical ReferenceMaterials
MarketingManager
•60-component MegaMix
™
includes six target gases—eliminatesmixing errors.
•0.18mmRtx
®
-VMS column offers fast cycles, excellent resolution of gases.
•Monitor drinkingwater - wastewater - hazardouswaste.
benzene
bromobenzene
bromochloromethane
bromodichloromethane
bromoform
bromomethane (methyl bromide)
n
-butylbenzene
sec
-butylbenzene
tert
-butylbenzene
carbon tetrachloride
chlorobenzene
chloroethane (ethyl chloride)
chloroform
chloromethane (methyl chloride)
2-chlorotoluene
4-chlorotoluene
dibromochloromethane
1,2-dibromo-3-chloropropane
1,2-dibromoethane (EDB)
dibromomethane
1,2-dichlorobenzene
1,3-dichlorobenzene
1,4-dichlorobenzene
dichlorodifluoromethane (CFC-12)
1,1-dichloroethane
1,2-dichloroethane
1,1-dichloroethylene
cis
-1,2-dichloroethylene
trans
-1,2-dichloroethylene
1,2-dichloropropane
1,3-dichloropropane
2,2-dichloropropane
1,1-dichloropropene
trans
-1,3-dichloropropene
cis
-1,3-dichloropropylene
ethylbenzene
hexachloro-1,3-butadiene
(hexachlorobutadiene)
isopropylbenzene (cumene)
4-isopropyltoluene (
p
-cymene)
methylene chloride
(dichloromethane)
naphthalene
n
-propylbenzene
styrene
toluene
1,1,1,2-tetrachloroethane
1,1,2,2-tetrachloroethane
tetrachloroethylene
1,2,4-trichlorobenzene
1,2,3-trichlorobenzene
1,1,1-trichloroethane
1,1,2-trichloroethane
trichloroethylene
trichlorofluoromethane (CFC-11)
1,2,3-trichloropropane
1,3,5-trimethylbenzene
1,2,4-trimethylbenzene
vinyl chloride
m
-xylene
o
-xylene
p
-xylene
VolatilesMegaMix
™
with
Gases
(60Components)
Each
5-pk.
10-pk.
200µg/mL each in P&Tmethanol, 1mL/ampul
30603
$85
30603-510
$382.50
—
w/data pack
30603-500
$95
30603-520
$392.50
30703
$722.50
Rtx
®
-VMSColumns (fusedsilica)
benzene
bromobenzene
bromochloromethane
bromodichloromethane
bromoform
n
-butylbenzene
sec
-butylbenzene
tert
-butylbenzene
carbon tetrachloride
chlorobenzene
chloroform
2-chlorotoluene
4-chlorotoluene
dibromochloromethane
1,2-dibromo-3-chloropropane
1,2-dibromoethane
dibromomethane
1,2-dichlorobenzene
1,3-dichlorobenzene
1,4-dichlorobenzene
1,1-dichloroethane
1,2-dichloroethane
1,1-dichloroethene
cis
-1,2-dichloroethene
trans
-1,2-dichloroethene
1,2-dichloropropane
1,3-dichloropropane
2,2-dichloropropane
1,1-dichloropropene
cis
-1,3-dichloropropene
trans
-1,3-dichloropropene
ethylbenzene
hexachlorobutadiene
isopropylbenzene
p
-isopropyltoluene
methylene chloride
naphthalene
n
-propylbenzene
styrene
1,1,1,2-tetrachloroethane
1,1,2,2-tetrachloroethane
tetrachloroethene
toluene
1,2,3-trichlorobenzene
1,2,4-trichlorobenzene
1,1,1-trichloroethane
1,1,2-trichloroethane
trichloroethene
1,2,3-trichloropropane
1,2,4-trimethylbenzene
1,3,5-trimethylbenzene
m
-xylene
o
-xylene
p
-xylene
502.2MegaMix
™
(54Components)
Each
5-pk.
10-pk.
200µg/mL each in P&Tmethanol, 1mL/ampul
30432
$56.70
30432-510
$249.70
—
w/data pack
30432-500
$67
30432-520
$277.10
30532
$484.20
2,000µg/mL each in P&Tmethanol, 1mL/ampul
30431
$78.30
30431-510
$348.20
—
w/data pack
30431-500
$88.60
30431-520
$386.80
30531
$676
bromomethane
chloroethane
chloromethane
dichlorodifluoromethane
trichlorofluoromethane
vinyl chloride
502.2CalibrationMix#1 (gases)
Each
5-pk.
10-pk.
200µg/mL each in P&Tmethanol, 1mL/ampul
30439
$23.70
30439-510
$103.60
—
w/data pack
30439-500
$34
30439-520
$114.70
30539
$201
2,000µg/mL each in P&Tmethanol, 1mL/ampul
30042
$34
30042-510
$151.30
—
w/data pack
30042-500
$44.30
30042-520
$167.50
30142
$292.40
(temp. limits -40°C to 240/260°C)
0.18mm ID, 1.00µm df
20-Meter, cat.# 49914,
$375
40-Meter, cat.# 49915,
$650
