An analytical methodology has been developed for the direct analysis of neutral nitrogen compounds in diesel oil by HPLC with subsequent detection using MS and/or photodiode-array UV spectrometry. By diluting diesel oils with one volume of hexane, diesel samples could be injected directly onto an alumina analytical column and then eluted with a gradient mobile phase consisting of hexane and dioxane. Nitrogen compounds were selectively retained on the alumina column, eluted using LC, and then detected by particle beam LC-MS or UV at 254, 270 and 290 nm. Two Brazilian and one Arabian diesel distillates were investigated. Alkylcarbazoles and alkylindoles were identified as the major neutral nitrogen components. Structural identification was accomplished by combination of electron impact MS and UV analyses. The concentration of carbazoles and indoles was estimated using calibration standards of carbazole and indole, respectively.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Organic Chemistry