12. Procedure
12.1 Preparation of Apparatus - After optimization of the carrier gas pressure (9.3) and evaluation of apparatus (Section 10), set the temperature program corresponding to the selected method (Table 1).
12.2 Injection ofSample - Inject with a 5 or 10 µl syringe, manually or by autosampler, the size corresponding to the method (Table 1).
12.3 Integration ofChromatogram - Integration codes must be selected to obtain a horizontal baseline with a perpendicular drop to the baseline for partially resolved peaks. An example of correct baseline is given in Figs. A1.1 and A1.2.
12.4 Identification - Each peak is identified by matching the retention time with that ofcompounds listed in Table 1 or Table 2 and standard chromatogram given in Fig. A1.1 or Fig. A1.2. A specific software program using the data of Table 1 or Table 2 can be employed.
12.4.1 If an oxygenate has been determined by Test Methods D4815 or D5599 and is not in the table, it is necessary to prepare a mixture of a weighed amount of this oxygenate in a known spark-ignition engine fuel to determine its retention time and response factor and then add it to the table.
13. Calculation
13.1 Calculation of% (m/m) of Each Compound Without Co-elution and Not Corrected for Co-elutions - % (m/m) of each component without co-elution and no corrections of co-elutions is calculated according to Eq 6:
where:
Ci' = % (m/m) of compound i without co-elution and no correction of coelutions,
Ai = peak area of compound i without co-elution (benzene, toluene, and oxygenates),
Aint = peak area of compounds co-eluting (benzene, toluene, and oxygenates),
Bi = response factor for component i (given in Table A1.1 or Table A1.2), and
Bint = response factor for components co-eluted with benzene, toluene, and oxygenates.
13.2 Calculation of Components Coeluted with Benzene, Toluene, and Oxygenates - Benzene and toluene contents are determined by Test Methods D3606 or D4420 or D5580; oxygenates content is determined by Test Methods D4815 or D5599. The % (m/m) of components coeluted with benzene, toluene, and oxygenates is calculated according Eq 7:
where:
Ccoeluted = % (m/m) of component eluted with benzene, toluene, or oxygenates,
Cint = % (m/m) calculated with Eq 6 for the peak with co-elution,
Cext = % (m/m) of benzene, toluene, or oxygenates determined by other method, and
Bext = response factor of benzene, toluene, or oxygenates.
13.3 Calculation of Other Components - % (m/m) of other components is calculated using Eq 8:
