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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 8270 MegaMix™ ,
is supplemented (cat.# 31291), to double the on-
column concentration for this low-level calibration
(<20ng on column).
For analysts who cannot use the MegaMix™, we offer
six simpler calibration mixes of Method 8270 semi-
volatiles, formulated by chemical class (8270
Calibration Mix #1—8270 Calibration Mix #6, cat.#s
31618 –31623, described in the 2004 Restek cata-
log, page 359), and Organochlorine Pesticide Mix
AB #3 (cat.# 32415, catalog page 358). EPA
Appendix IX Mix #1 and Appendix IX Mix #2 (cat.#s
31625 and 31806, catalog page 358) complement
this full set of mixes.
We developed each of these mixes, including the
MegaMix ™ mix, for maximum 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 in Method 8270D, readily oxidizes to
diphenylamine and nitric oxide, a highly reactive gas
that can participate in many chemical reactions or
act as a catalyst for other oxidation and reduction
reactions in the mix. Consequently, we include
diphenylamine, rather than N-nitrosodiphenylamine,
in the 8270 MegaMix™ mix, to prevent degradation
of other components of the mix. Another target com-
pound, diphenylhydrazine, also oxidizes easily, form-
ing azobenzene, so we include azobenzene in the
8270 MegaMix™ mix to assure stability. The stability
of an unopened ampul of 8270 MegaMix ™ mix is 18
months, as determined by real-time analysis.
In addition to the best choice for analytical column,
and stable calibration mixtures, we also have avail-
able internal and surrogate standards and the tun-
ing compound recommended in Method 8270D: SV
Internal Standard Mix, Acid Surrogate Mix (4/89
SOW), and B/N Surrogate Mix (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 an Rtx®-5Sil MS col-
umn and our 8270 MegaMix™ 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 Semivolatile Organic Analytes
Using a 0.18mm ID Rtx® -5Sil MS Column, continued from page 3
Rtx®-35 Amine 30m, 0.25mm ID, 0.50µm (cat.# 11338)
1.0µL split injection of underivatized cold medicines
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 7 min.)
Det.: MSD
Scan range: 40–450amu
Ionization: EI
Mode: scan
Figure 3 An Rtx®-35 Amine column simplifies GC/MS analysis of common cold and flu medications.
1. guaifenesin
2. pheniramine
3. phenyltoloxamine
4. chlorpheniramine
5. brompheniramine
6. dextromethorphan
7. pyrilamine
8. triprolidine
9. codeine
10. hydrocodone
GC_PH00575
Rtx®-35 Amine Columns (fused silica)
(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-Deactivated Guard Columns
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). For more information on guard columns,
see our 2004 Chromatography Products Guide(lit.
cat.# 59854).
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