Figure 3–MSdetectionof a flash splitless 2µL injectionpositively
identifies theoxygenates andpentanes.
1
2
3
4
5
6
7
8
30m, 0.45mm, 2.55µmRtx
®
-VGC (cat.# 19408);
splitless injectionw/ 0.5min. purge off;
Compounds in at 100ppm
Oven program:
35°C (hold 5min.);
Carrier gas:
helium@ ~8mL/min.;
Detector:
Agilent 5971A;
Scan range:
35 to 200 AMU.
1. pentane
2. ethanol
3. 2-methylpentane
4. 3-methylpentane
5. MTBE
6. tert-butylalcohol
7. DIPE
8. ETBE
Figure 4–Using theRtx-VGC column and a PIDmakes possible the identification of
most oxygenates in a gasoline standard.
1
4
5
3
2
6
7
8
9
10
11
12
30m, 0.45mm, 2.55µmRtx
®
-VGC (cat.# 19408); 500ppb in 5mL of RO
water;
GC:
Finnigan 9001
;
Oven program:
40°C (hold 2min.) to 130°C
@ 6°C/min. (hold 0min.) to 230°C@ 30°C/min. (hold 2min.)
;
Carrier
gas:
helium@ ~8mL/min.;
Detector:
Finnigan PID, make up 7mLmin.,
purge 7mL/min., set @ 0.35mV, base temperature 200°C.
1. benzene
2. toluene
3. ethylbenzene
4. m/p-xylene
5. o-xylene
6. isopropylbenzene
7. ethylmethylbenzene
8. 1,2,3-trimethylbenzene
9. 1,2,4-trimethylbenzene
10. napthalene
11. 2-methylnapthalene
12. 1-methylnapthalene
GC_EV00467
GC_EV00466
p
-xylene onmany capillary columns, it is difficult to separate from
the aromatic compounds found in gasoline. The Rtx
®
-VGC column
resolves chlorobenzene from the other aromatic compounds, allow-
ing quantitation by PID (Figure 5).
The excellent resolution achieved by the Rtx
®
-VGC column pre-
ventsmisidentifications commonwith PID and FID. GC/MSmeth-
ods provide positive identification of coeluting analytes, but
the right column can avoid coelutions of compounds that
share quantitation ions. The Rtx
®
-VGC column is selective,
has a programmable temperature limit of 260°C, and
exhibits exceptional low bleed at common operating temper-
atures of 230°C. It is an ideal choice for analyzing gasoline
additives in GRO samples.
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