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Figure 2 Use an Rxi®-5Sil MS column to easily resolve a broad
range of pesticide chemistries in a single run (500pg).
2008 vol. 3
values less than 0.990, such as acephate, omethoate,
and dicofol, show a more linear response when ana-
lyzed in matrix. As shown in Figure 1, the Rxi®-5Sil
MS column is also highly inert, producing excellent
peak shape even for difficult compounds such as
acephate. The linearity, sensitivity, and inertness
demonstrated here, make the Rxi®-5Sil MS column
ideal for more accurate low level quantification of
active compounds.
Low Bleed, High Selectivitity
Another crucial characteristic for multiresidue
pesticide methods is column bleed. Minimizing
bleed is critical in preventing interference with
target compounds, even in SIM analysis, as some
compounds may share ions and have similar bleed
spectra. As shown in the TIC chromatogram in
Figure 2, the ultra-low bleed of the Rxi®-5Sil MS
column allows full scan analysis with minimal
interference from column bleed. The Rxi®-5Sil MS
column provides excellent separation for the wide
range of chemistries tested and the column is also
selective enough to easily separate isomers, such as
permethrin I and II.
In summary, many of the difficulties associated
with multiresidue methods are simplified by using
the Rxi®-5Sil MS column. Its outstanding inert-
ness, low bleed at high temperatures, and unique
selectivity provide a robust capillary column with
the sensitivity and longevity needed to address the
tough challenges inherent to low level multiresidue
pesticide analysis.
Figure 1 Outstanding peak symmetry for active compounds
demonstrates column inertness (500pg).
1. methamidophos
2. dichlorvos
3. bromonitrobenzene (IS)
4. mevinphos
5. acephate
6. o-phenylphenol
7. omethoate
8. dimethoate
9. pentachloronitrobenzene (IS)
10. diazinon
11. chlorothalonil
12. vinclozolin
Column: Rxi®-5Sil MS, 30m, 0.25mm ID, 0.25µm (cat.# 13623),
with 5m x 0.25mm ID Rxi® deactivated guard tubing (cat.# 10029)
Instrument: PerkinElmer Clarus 500 GC/MS
Sample: 1ppm each compound (custom mixes)
1ppm triphenylphosphate (cat.# 32281)
1ppm 1-bromo-2-nitrobenzene (cat.# 32279)
1ppm pentachloronitrobenzene (cat.# 32091)
Inj.: 0.5µL splitless (hold 1 min.),
PSS Drilled Uniliner® (hole near bottom) inlet liner (cat.# 22989)
Inj. temp.: 250°C
Carrier gas: helium, constant flow
Linear velocity: 32cm/sec. @ 90°C
Oven temp.: 90°C (hold 1 min.) to 310°C @ 10°C/min. (hold 5 min.)
Det.: MS
Transfer line temp: 300°C
Scan range: 50-350amu
Ionization: EI
Mode: scan
GC_EV01034
GC_EV01036
1. acephate
13. carbaryl
14. metalaxyl
15. dichlofluanid
16. malathion
17. thiabendazole
18. captan
19. folpet
20. imazalil
21. myclobutanil
22. endrin
23. fenhexamid
24. 4,4’-DDT
25. propargite
26. triphenylphosphate (IS)
27. iprodione
28. bifenthrin
29. fenpropathrin
30. dicofol
31. permethrin I
32. permethrin II
33. deltamethrin
* septum bleed
Product Listing
Rxi®-5Sil MS Columns (fused silica)
(Crossbond®, selectivity close to 5% diphenyl/95% dimethyl polysiloxane)
ID df (µm) temp. limits length cat. # price
0.25mm 0.25 -60 to 330/350°C 30-Meter 13623
Rxi® Guard/Retention Gap Column
Nominal ID Nominal OD 5-Meter
0.32mm 0.45 ± 0.04mm 10039
PSS Liners for PerkinElmer GCs
ID* x OD & Length (mm) qty. cat.# price
PSS Drilled Uniliner (hole near bottom)
20mm x 4.0mm x 86.2mm 5-pk. 22989
The inertness of the
Rxi®-5Sil MS column
ensures linear performance
down to 10pg on-column,
allowing more accurate
low level quantification.
See Figure 2 for conditions.
800-356-1688 •