ASTM D2425 for Hydrocarbon Types in Middle Distillates by Mass Spectrometry
1. Scope
1.1 This test method covers an analytical scheme using the mass spectrometer to determine the hydrocarbon types present in virgin middle distillates 204 to 343°C (400 to 650°F) boiling range, 5 to 95 volume % as determined by Test Method D86. Samples with average carbon number value of paraffins between C12 and C16 and containing paraffins from C10 and C18 can be analyzed. Eleven hydrocarbon types are determined. These include: paraffins, noncondensed cycloparaffins, condensed dicycloparaffins, condensed tricycloparaffins, alkylbenzenes, indans or tetralins, or both, CnH2n-10 (indenes, etc.), naphthalenes, CnH2n-14 (acenaphthenes, etc.), CnH2n-16 (acenaphthylenes, etc.), and tricyclic aromatics.
NOTE 1 - This test method was developed on consolidated Electro-dynamics Corp. Type 103 Mass Spectrometers.
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see 10.1.
2. Referenced Documents
2.1 ASTM Standards:
D6 Test Method for Distillation of Petroleum Products at Atmospheric Pressure
D549 Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography
3. Terminology
3.1 The summation of characteristic mass fragments are defined as follows:
∑71 (paraffins) = total peak height of m/e + 71 + 85.
∑67 (mono or noncondensed polycycloparaffins, or both) = total peak height of m/e + 67 + 68 + 69 + 81 + 82 + 83 + 96 + 97.
∑123 (condensed dicycloparaffins) = total peak height of m/e +123 + 124 + 137 + 138 + ••• etc. up to 249 + 250.
∑149 (condensed tricycloparaffins) = total peak height of m/e +149 + 150 + 163 + 164 + ••• etc. up to 247 + 248.
∑91 (alkyl benzenes) = total peak height of m/e + 91 + 92 + 105 + 106 + ••• etc. up to 175 + 176.
∑103 (indans or tetralins, or both) = total peak height of m/e + 103 + 104 + 117 + 118 + ••• etc. up to 187 + 188.
∑115 (indenes or CnH2n-10, or both) = total peak height of + m/e 115 + 116 + 129 + 130 + ••• etc. up to 185 + 186.
128 (naphthalene) = total peak height of m/e + 128.
∑141 (naphthalenes) = total peak height of m/e + 141 + 142 + 155 + 156 + ••• etc. up to 239 + 240.
∑153 (acenaphthenes or C nH2n-14, or both) = total peak height of m/e + 153 + 154 + 167 + 168 + ••• etc. up to 251 + 252.
∑151 (acenaphthylenes or C nH2n-16, or both) = total peak height of m/e + 151 + 152 + 165 + 166 + ••• etc. up to 249 + 250.
∑177 (tricyclic aromatics) = total peak height of m/e + 177 + 178 + 191 + 192 + ••• etc. up to 247 + 248.
