175 / 298
the
in this issue
Specialty Reversed Phase
HPLC Columns for Polar Analytes
…pg. 4–5
Sulfinert
™
& Silcosteel
®
Ball & Plug
Valves & Tubing
…pg. 6
Analysis of European
Organophosphorus Pesticides
…pg. 7
New Analytical Reference Materials
…pg. 8–9
New Ultra HPLC Column for
Carbamates Analysis
…pg. 10
Analyzing Fatty Acid Methyl
Esters by GC
…pg. 11
Improved Responses for Chlorinated
Pesticides
…pg. 12–13
Peak Performers—GC/MS Tools &
Supplies
…pg. 14
Cool Tools for GC & HPLC
…pg. 15
Behind the Scenes
…pg. 16
800-356-1688
★
814-353-1300
www.restekcorp.com2002
vol. 4
Advantage
Optimized Analysis
of Volatile Organics
in Hazardous Waste
…pg. 1–2
Vespel
®
Ring Inlet Seal
…pg. 3
Leak Detective
™
II
Electronic Leak Detector
…pg. 3
new
Innovators of High Resolution
Chromatography Products
by Christopher English, Environmental Innovations Chemist
Optimized Analysis of Volatile
Organics in Hazardous Waste
Using an Rtx
®
-VMS GC/MS Column and New
Restek Reference Materials
✔
Rtx
®
-VMS polymer formulated specifically for volatiles analysis by GC/MS.
✔
Greater throughput—excellent separations and faster analyses for 100+ volatiles
and associated compounds.
✔
Excellent sensitivity—high thermal stability minimizes bleed.
✔
Convenience—8260B Calibration Mix #1A is a stable mixture of 76 + 1 volatiles.
Accurate and rapid analyses of over 100 volatile
organic compounds (VOCs), in a wide range of
matrices, are a major challenge to environmental
laboratories. US EPA Method 8260B, described in
US EPA SW-846, is widely used as a guideline for
analyses of VOCs in hazardous waste, sludges, or
other discarded material, prior to depositing these
materials in hazardous waste facilities. The method
also is followed for monitoring ground water at
these facilities.
Restek chemists designed the Rtx
®
-
VMS column to address the
large—and increasing—
number of analytes listed
in US EPA Methods 8260
and 524.2, plus unlisted
but commonly encoun-
tered compounds, such
as acetates and oxy-
genates (ethers). With the
aid of computer modeling,
we tuned the stationary phase in
the Rtx
®
-VMS column specifically
toward resolving compounds that share common
quantification ions. This has improved selectivity,
reduced bleed, and shortened analysis time, relative
to traditional “624/1301” phases. In designing this
stationary phase we considered performance for
compounds that are not listed in the usual test
methods (e.g., acetates and oxygenates). We added
these compounds to the design criteria for the
Rtx
®
-VMS phase because many of them have been
discovered in ground water, and analysts in envi-
ronmental laboratories often add them to calibra-
tion mixes.
A 40m x 0.18mm ID x 1.0µm Rtx
®
-VMS column, and
the chromatographic conditions used to obtain
Figure 1 (page 2), are optimal for a 14-minute
analysis, which is less than the cycle time for a stan-
dard purge and trap unit. The conservative initial
temperature enhances the resolution between
tert
-
butyl alcohol and methyl
tert
-butyl ether (peaks 21
& 22)—the two analytes are baseline resolved under
these conditions. An initial temperature of 50°C or
lower enhances the resolution between
chloromethane and vinyl chloride (peaks 4 and 5).
Alternatively, an initial temperature of up to 60°C can
be used, to promote faster oven cycling and to pre-
vent large amounts of methanol from condensing at
the head of the column.
The Rtx
®
-VMS column is available in a wide variety
of internal diameters. Base your choice of ID and
column length on the number of target analytes in
your samples, and on your instrumentation.
We now offer a comprehensive acetates mix (cat.#
30489) and a comparable oxygenates mix (cat.#
30465), which complement our 8260B Calibration
Mix #1 of VOCs (cat.# 30475). These three refer-
ence solutions account for more than 80% of the
most common target compounds shown in Figure 1.
In volatiles analysis, oven cycle time and/or purge
and trap cycle time, not analysis time, are the fac-
tors that limit productivity. Because Rtx
®
-VMS
columns are designed for higher starting tempera-
tures, they shorten oven cycle times - and thus
increase sample throughput - without sacrificing
resolution of gaseous analytes. To see example
chromatograms, request a copy of our Rtx
®
-VMS
capillary columns flyer (lit. cat.# 59209A).