2. AOACRIChemContMethods-2018Awards

490  M astovska et al . : J ournal of AOAC I nternational V ol . 98, N o . 2, 2015

(1)

Injection volume, µL 1 1 1 10 5

Table 2014.08G. ( continued ) Laboratory No. 6 7 8 9 10

Pressure pulse and duration NA NA 50 psi for 0.2 min NA NA

MS transfer line temperature, °C 300 280 320 300 325 (3) (2)

PTV solvent vent pressure NA NA NA NA 50 kPa

Liner SGE, Focus liner Agilent, single taper, glass wool-packed, 4 mm id Agilent, double taper, 4 mm id Apex, ProSep taper liner, PTV solvent vent time NA NA NA NA 0.5 min 2 mm id 2 mm id

PTV solvent vent flow NA NA NA NA 100 mL/min

He flow/pressure program 1.5 mL/min (13 min), 10 mL/min 2 to 2 mL/min 1.5 mL/min (constant flow) 1 mL/min (constant flow) 1.3 mL/min (19.5 min), 50 mL/min 2 to 2 mL/min 2 mL/min (constant flow) Injection mode Hot splitless Hot splitless Pulsed splitless Splitless PTV solvent vent

Gas saver flow and start time 20 mL/min, 3 min 20 mL/min, 2 min 15 mL/min, 6 min NA 15 mL/min, 6 min

Split vent purge flow and start 50 mL/min, 1 min 50 mL/min, 1 min 50 mL/min, 1 min 50.0 mL/min, 2.30 min 100 mL/min, 3 min

50°C (0.5 min), 600°C/min 400°C (15 min), 30°C/min 70°C Agilent, PTV multi-baffle,

Inlet temperature (program) 300 ° C 280°C 320°C 60°C (2.25 min), 300°C/min to 335°C (45 min)

separation for benzo[ b ]fluoranthene, benzo[ j ]fluoranthene, and benzo[ k ]fluoranthene (concentration ratio of 1:1:1). Note : Criteria for separation of chrysene and triphenylene (another PAH critical pair) were not set for the collaborative study. For accurate quantitation of chrysene, at least 50% valley separation is recommended, which can be achieved using selective stationary phases. The maximum oven temperature program may not exceed the maximum temperature limit for a given column. Backbone-modified columns, such as Rxi-17Sil MS or DB-17MS, are recommended for their better temperature stability and also good selectivity for critical PAH pairs or groups, including the anthracene/phenanthrene pair or benzofluoranthenes. Conduct proper inlet and column Figure 2014.08C. GC separation criteria: ( 1 ) A baseline separation of ben benzo[ e ]pyrene (concentration ratio of 1:5), ( 2 ) at least 50% valley separ phenanthrene and anthracene (concentration ratio 2.5:1; evaluated for which is the second peak in the figure), and ( 3 ) at least 50% valley separ benzo[ b ]fluoranthene, benzo[ j ]fluoranthene, and benzo[ k ]fluoranthene of 1:1:1). Figure 2014.08C. GC separation criteria: (1) A baseline separation of benzo[ a ]pyrene and benzo[ e ]py ene (concentr tio ratio of 1:5), (2) at least 50% valley s parati of phenanthrene and anthracene (concentration ratio 2.5:1; evaluated for the anthracene peak, which is the second peak in the figure), and (3) at least 50% valley separation for benzo[ b ]fluoranthene, benzo[ j ]fluoranthene, and benzo[ k ]fluoranthene (concentration r tio of 1:1:1).