Air Monitoring: New Advances in Sampling and Detection

Table 10

Sampling and analytical conditions.

TD conditions	GC conditions	MS conditions
Configuration: TD-100 for automated tube desorption (Markes International Ltd); Flow path temperature: 150°C; Cold trap: Air Toxics Analyser type trap; Trapping temperature: 25°C; Cold trap desorption: 300°C for 3 min (10 : 1 split); Trap heating rate: 40°C/s	Column: 60 m × 0.32 mm × 1.8 μm, 624 type phase; Oven: 35°C (5 min) 5°C/min to 230°C (0 min); Constant flow: 1.7 mL/min at 35°C	Quadrupole MS conditions; Source temperature: 230°C; Quadrupole temperature: 150°C; Transfer line temperature: 280°C; Scan range: m/z 25–300; SIM ions: 29, 43, 53, 57, 67, 78, 82, 91, 105, and 120; TOF MS conditions; Configuration: BenchTOF-dx (ALMSCO International Ltd, UK); Ion source heating: 240°C; Transfer line temperature: 240°C; Acquisition rate: 2 data points/s (5000 spectra/data point); Mass range: m/z 25–500

Sampling: 500 mL of hydrocarbon standard taken onto a multi-bed sorbent tube using five pulls of the piston pump set at 100 mL volume per pull*.
*Note that setting the split ratio at 10 : 1 enabled 90% of the sample to be recollected for repeat analysis. The order of analyses was as follows: quad scan (100% level), quad SIM (90% level), then TOF (81% level).