800-356-1688
• 5 •
For stability, two analytes in Figure 1, benzoic acid
and benzidine, are introduced separately (cat.#
31415 and cat.# 31441, respectively). 2,4-
Dinitrophenol, a component of the 8270MegaMix
™
,
is supplemented (cat.# 31291), to double the on-
column concentration for this low-level calibration
(<20ng on column).
For analysts who cannot use theMegaMix
™
, we offer
six simpler calibrationmixes of Method 8270 semi-
volatiles, formulated by chemical class (8270
CalibrationMix #1—8270 CalibrationMix #6, cat.#s
31618–31623, described in the 2004Restek cata-
log, page 359), andOrganochlorine PesticideMix
AB #3 (cat.# 32415, catalog page 358). EPA
Appendix IXMix #1 and Appendix IXMix #2 (cat.#s
31625 and 31806, catalog page 358) complement
this full set of mixes.
We developed each of thesemixes, including the
MegaMix
™
mix, formaximum stability, through care-
ful consideration of chemical properties of all poten-
tial components. Because 3-methylphenol and 4-
methylphenol coelute, we include each in the 8270
MegaMix
™
mix at half the concentration of the other
components, to enable the user to calibrate at lower
levels to quantify these compounds at the required
limits. N-nitrosodiphenylamine, an amine target
compound inMethod 8270D, readily oxidizes to
diphenylamine and nitric oxide, a highly reactive gas
that can participate inmany chemical reactions or
act as a catalyst for other oxidation and reduction
reactions in themix. Consequently, we include
diphenylamine, rather thanN-nitrosodiphenylamine,
in the 8270MegaMix
™
mix, to prevent degradation
of other components of themix. Another target com-
pound, diphenylhydrazine, also oxidizes easily, form-
ing azobenzene, sowe include azobenzene in the
8270MegaMix
™
mix to assure stability. The stability
of an unopened ampul of 8270MegaMix
™
mix is 18
months, as determined by real-time analysis.
In addition to the best choice for analytical column,
and stable calibrationmixtures, we also have avail-
able internal and surrogate standards and the tun-
ing compound recommended inMethod 8270D: SV
Internal StandardMix, Acid SurrogateMix (4/89
SOW), and B/N SurrogateMix (4/89 SOW),
described here (see page 3), and PFTBA (MS
Tuning Compound), cat.# 30482, described on
catalog page 357.
If you are analyzing for semivolatile compounds by
GC/MS, we suggest you evaluate anRtx
®
-5Sil MS col-
umn and our 8270MegaMix
™
and other reference
mixes. Rtx
®
-5Sil MS columns are available in all
common dimensions, or you can use the short, thin-
film 20m, 0.18mm ID, 0.18µm column for fastest
analyses and highest productivity.
Fast Analysis of SemivolatileOrganic Analytes
Using a 0.18mm IDRtx
®
-5Sil MSColumn, continued from page 3
Rtx
®
-35 Amine 30m, 0.25mm ID, 0.50µm (cat.# 11338)
1.0µL split injection of underivatized coldmedicines
Conc.:
1000ng/µL
Inj. temp:
250°C
Carrier gas:
helium
Linear velocity:
30cm/sec.
Oven temp.:
250°C to 300°C@ 7°C/min. (hold 7min.)
Det.:
MSD
Scan range:
40–450amu
Ionization:
EI
Mode:
scan
Figure3
AnRtx®-35Amine column simplifiesGC/MSanalysisof common coldand flumedications.
1. guaifenesin
2. pheniramine
3. phenyltoloxamine
4. chlorpheniramine
5. brompheniramine
6. dextromethorphan
7. pyrilamine
8. triprolidine
9. codeine
10. hydrocodone
GC_PH00575
Rtx®-35AmineColumns (fusedsilica)
(Crossbond
®
35% diphenyl/65% dimethyl polysiloxane)
ID
df (µm)
temp. limits
15-Meter
30-Meter
0.25mm 0.50
0 to 290/310°C
11335
11338
1.00
0 to 280/300°C
11350
11353
0.32mm 1.00
0 to 280/300°C
11351
11354
1.50
0 to 270/290°C
11366
11369
0.53mm 1.00
0 to 260/280°C
11352
11355
3.00
0 to 240/260°C
11382
11385
Base-DeactivatedGuardColumns
For analyzing basic compounds, use a
base-deactivated guard column. For a 5m base-
deactivated guard column, order cat.# 10000 ($45),
10001 ($50), or 10002 ($65) (0.25, 0.32, or 0.53mm ID,
respectively). Formore information on guard columns,
see our 2004
Chromatography Products Guide
(lit.
cat.# 59854).
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