1.1 This detailed hydrocarbon analysis (DHA) test method covers the determination of hydrocarbon components paraffins, naphthenes, and monoaromatics (PNA) of petroleum naphthas as enumerated in Table 1 . Components eluting after n -nonane (bp 150.8°C) are determined as a single group. TABLE 1 Typical Retention Characteristics of Naphtha Components Note 1 - The abbreviations N and P refer to unidentified naphthenes and paraffins respectively. Compound Retention Time, min Adjusted Retention Time, min Kovats Retention Index @ 35°C Linear Retention Index Methane 3.57 0.00 100.0 ... Ethane 3.65 0.08 200.0 ... Propane 3.84 0.27 300.0 ... Isobutane 4.14 0.57 367.3 ... n -Butane 4.39 0.82 400.0 ... 2,2 -Dimethylpropane 4.53 0.96 415.5 ... Isopentane 5.33 1.76 475.0 ... n -Pentane 5.84 2.27 500.0 ... 2,2 -Dimethylbutane 6.81 3.24 536.2 ... Cyclopentane 7.83 4.26 564.1 ... 2,3 -Dimethylbutane 7.89 4.32 565.5 ... 2 -Methylpentane 8.06 4.49 569.5 ... 3 -Methylpentane 8.72 5.15 583.4 ... n -Hexane 9.63 6.06 600.0 ... 2,2 -Dimethylpentane 11.22 7.65 624.2 ... Methylcyclopentane 11.39 7.82 626.5 ... 2,4 -Dimethylpentane 11.68 8.11 630.3 ... 2,2,3 -Trimethylbutane 12.09 8.52 635.4 ... Benzene 13.29 9.72 649.1 ... 3,3 -dimethylpentane 13.84 10.27 654.8 ... Cyclohexane 14.19 10.62 658.3 ... 2 -Methylhexane 15.20 11.63 667.8 ... 2,3 -Dimethylpentane 15.35 11.78 669.1 ... 1,1 -Dimethylcyclopentane 15.61 12.04 671.4 ... 3 -Methylhexane 16.18 12.61 676.2 ... cis-1,3 -Dimethylcyclopentane ...