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www.restek.com2005 vol. 3
Capillary GC stationary phases for organochlorine pesticides (e.g. US EPA
Method 8081) must possess the selectivity needed to resolve target pesticides,
yet withstand the rigors of repeated injections of extracts containing harsh
residuals from the sample matrix. The US EPA method also requires a suitable
counterpart column for confirmation, to quantify potential pesticide “hits.”
An efficient way to meet these requirements is through dual column analysis,
which eliminates the need for a separate confirmation run, or GC/MS analy-
sis. A newly enhanced version of our Rtx®-CLPesticides2 column, with
dimensions of 30m x 0.32mm ID x 0.50µm (cat.# 11325) is now available for
this application. The Rtx®-CLPesticides2 column, coupled with an Rtx®-440
column of the same dimensions (cat.# 12939), can provide a complete sepa-
ration of the 20 most commonly analyzed organochlorine pesticides, listed in
Method 8081, in less than 12 minutes (Figure 1).
The unique selectivities of the Rtx®-CLPesticides2 column and the Rtx®-440
column enable the analysis to be run quickly, with good resolution and peak
shapes, as shown in Figure 1. Both columns produce similar run times, with a
set of elution order inversions and, because they share a common stationary
phase thickness, they should exhibit similar life expectancies. For accurate,
time-saving analyses of organochlorine pesticides, we highly recommend the
Rtx®-CLPesticides2 / Rtx®-440 column combination.
Rapid, Dual Column Analysis for Organochlorine Pesticides
12-Minute Analysis Using Rtx®-CLPesticides2 / Rtx®-440 Capillary GC Columns
By Jason Thomas, Environmental Innovations Chemist
• Analysis and confirmation with a single injection.
• Rapid analysis increases throughput.
• New, thicker Rtx®-CLPesticides2 phase increases column lifetime.
Rtx®-CLPesticides2 Column (fused silica)
ID
df (µm) temp. limits
length cat. #
0.32mm 0.50 -60 to 320/340°C 30-Meter 11325
Rtx®-440 Column (fused silica)
ID
df (µm) temp. limits
length cat. #
0.25mm 0.25 20°C to 320/340°C 30-Meter 12923
SeCure™“Y”Connector Kit
SeCure
™
“Y” connector body, 3 knurled nuts,
“Y” Universal Press-Tight
®
union, 3 ferrules.
Ferrules Fit Column ID qty.
cat.#
0.28/0.32mm
kit
20277
Organochlorine Pesticide Mix AB #2
20 components, listed in Figure 1, 8-80µg/mL in hexane:toluene
(1:1), 1mL/ampul
cat. # 32292
decachlorobiphenyl
2,4,5,6-tetrachloro-
m
-xylene
Pesticide Surrogate Mix
200µg/mL each in acetone, 1mL/ampul
cat. # 32000
Figure 1
Sub-12-minute dual column analysis of organochlorine pesticides,
using an Rtx®CLPesticides2/Rtx®-440 column pair.
GC_EV00777
1. 2,4,5,6-tetrachloro-
m
-xylene (surr.)
2.
α
-BHC
3.
γ
-BHC
4.
β
-BHC
5.
δ
-BHC
6. heptachlor
7. aldrin
8. heptachlor epoxide
9.
γ
-chlordane
10.
α
-chlordane
11. endosulfan I
12. 4,4'-DDE
13. dieldrin
14. endrin
15. 4,4'-DDD
16. endosulfan II
17. endrin aldehyde
18. 4,4'-DDT
19. endosulfan sulfate
20. methoxychlor
21. endrin ketone
22. decachlorobiphenyl (surr.)
GC_EV00776
Column:
Rtx
®
-CLPesticides2 30m, 0.32mm ID, 0.50µm (cat.# 11325) and Rtx
®
-440 30m, 0.32mm ID,
0.50µm (cat.# 12939) with 5m x 0.32mm ID Siltek
®
treated guard
tubing (cat.# 10027), connected using SeCure
™
“Y” Connector Kit (cat.# 20277) with
Universal “Y” Press-Tight
®
Connector
Sample:
Organochlorine Pesticide Mix AB #2, 8-80µg/mL each component in hexane/toluene (cat.# 32292),
Pesticide Surrogate Mix, 200µg/mL each component in acetone (cat.# 32000)
Inj.:
0.5µL splitless (hold 0.75 min.), 3.5mm Siltek
®
treated single gooseneck inlet liner (cat.# 20961)
Inj. temp.:
250°C
Carrier gas:
hydrogen, constant pressure
Linear velocity: 60cm/sec. @ 300°C
Oven temp.:
110°C (hold 0.5 min) to 230°C @ 25°C/min., to 330°C @ 15°C/min. (hold 1 min.)
Det.:
ECD @ 330°C
Instrument:
Shimadzu GC-2010 FID/ECD with AOC-20i autosampler
for
more
info
For many additional pesticides
reference mixes, please refer to
our catalog, or visit our website.