Table 2.

Accuracy of Retention Projections Under a Range of Experimental Conditions

Experimental Condition	Accuracy of Retention Projectionsa
3.1.1 Metal blocks in the GC oven
Without blocks in oven	±0.43 s
With two Al blocks in oven	±0.35 s
3.1.2 Liner make/model/geometry
Agilent, 2 mm ID, 78.5 mm long, straight splitless, quartz	±0.49 s
Agilent, 4 mm ID, 78.5 mm long, gooseneck, glass	±0.44 s
SGE, 4 mm ID, 78.5 mm long, straight, glass	±0.38 s
Restek Siltek, 2 mm ID, 78.5 mm long, straight splitless, quartz	±0.45 s
Restek Sky, 4 mm ID, 78.5 mm long, straight, glass, packed w/deactivated glass wool	±0.40 s
Supelco, 4 mm ID, 78.5 mm long, straight, glass, packed w/deactived glass wool	±0.40 s
Thermo, 5 mm ID, 105 mm long, straight FocusLiner, packed w/deactived quartz wool	±0.42 s
Thermo, 5 mm ID, 105 mm long, straight, packed w/deactived quartz wool	±0.43 s
3.1.3 Injection history
Before injections	±0.51 s
After 7 injections of the urine sample	±1.3 s
Clean liner	±0.43 s
Dirty liner	±1.7 s
Clean base seal	±0.47 s
Dirty base seal	±0.50 s
3.1.4 Split or splitless injection
Split (10:1)	±0.42 s
Splitless	±0.43 s
3.1.5 Manual injection speed
Fast (~0.5 sec)	±0.42 s
Slow (5 sec)	±0.44 s
3.1.6 Inlet temperature
300ºC	±0.44 s
290 ºC	±0.42 s
280 ºC	±0.44 s
270 ºC	±0.43 s
250 ºC	±0.48 s
230 ºC	±0.45 s
200 ºC	±0.44 s
3.1.7 Column cut
Straight	±0.42 s
Angled	±0.45 s
3.1.8 Length of column in inlet
0.2 cm	±0.44 s
1.2 cm	±0.39 s
2.2 cm	±0.37 s
3.1.9 Column conditioning
None	±0.42 s
3 hrs at 320ºC	±0.45 s
3.1.10 Exposure to O2 levels in industrial grade He
Before	±0.42 s
After 72 hours exposure to 6.2 ppm O2 at 320ºC	±0.39 s
3.1.11 Transfer line temperature
320 ºC	±0.44 s
280 ºC	±0.53 s
240 ºC	±0.57 s
200 ºC	±0.63 s
160 ºC	±0.66 s
3.1.12 MS source temperature
300 ºC	±0.52 s
220 ºC	±0.50 s
180 ºC	±0.49 s
100 ºC	±0.52 s
3.1.13 Injection amount
1 pmol	±0.59 s
10 pmol	±0.50 s
20 pmol	±0.49 s
30 pmol	±0.50 s
50 pmol	±0.64 s
100 pmol	±1.1 s
750 pmol	±5.5 s
3.1.14 Column length
30 m	±0.44 s
25 m
20 m
15 m
3.1.15 Column inner diameter
0.25 mm	±0.44 s
0.32 mm
3.1.16 Film thickness
0.25 μm	±0.44 s
1 μm

^aAccuracy of retention projections is given as the root-mean-square error (experimental minus predicted retention time) among all 12 test compounds. indicates the accuracy is within the threshold for a “passed” system suitability check, indicates “passed, but questionable”, and indicates “failed”.

^bAccuracy of retention times calculated from linear retention indices that were measured under the standard 26 °C/min ramp with a 30 m column of 0.25 mm ID and 0.25 μm film thickness.

^cAfter correction for the difference from the nominal inner diameter

^dAfter correction for the difference from the nominal film thickness