APPLICATION NOTE Determination of 2-EthylHexylNitrate in Diesel Fuels by Gas Chromatography Robust Analysis with Deans Switch Technology Excellent Repeatability & Linearity No sample preparation Quantification range 50 – 4000 ppm Keywords: 2-EthylHexylNitrate (2-EHN), Cetane Improver, Diesel , Deans switch ANALYSIS The sample is introduced through the Split/Splitless inlet on the first column. 2-EHN including co-eluting compounds are diverted to the second column by Deans heart-cutting (fig 2). On the second column, the 2-EHN is separated from the co-eluting compounds (fig 3). Detection is done by the Flame Ionization Detector. Aux analysis column 2 – EthylHexylNitrate (2-EHN) is the most widely used Cetane improver for Diesel. 2-EHN improves fuel efficiency and increase Cetane Numbers of Diesel, thus offering larger flexibility to refiners to improve diesel fuel quality and maximizing refinery yields. AC Analytical Controls provides an accurate and precise total solution for the determination of 2EHN in diesel. Figure 1: Flow diagram 2-EHN in diesel on 6850 GC SOLUTION In complex sample matrixes like Diesel, single column applications often do not allow enough resolution to determine compound(s) of interest. The presented solution consists of a two dimensional column set-up in a Deans switch configuration. The Deans heart cut with different stationary phases in each dimension allows sufficient resolution required to determine 2-EHN in diesel fuels. This set-up allows neat sample injection and eliminates the need for sample preparation prior to injection. Figure 2: Precolumn separation, Heart-cutting (Monitor column connected to FID) www.paclp.com USA FRANCE GERMANY NETHERLANDS UAE RUSSIA CHINA SINGAPORE SOUTH KOREA THAILAND INDIA

APPLICATION NOTE The Concentration and Retention time repeatability of the application are determined using a 790 ppm Wt standard solution of 2-EHN in diesel. Results are summarized in Table 1) Figure 3: Separation of 100 ppm 2–EHN in diesel on analytical column Table 1: Repeatability of analysis (n=10) The linearity of the system is checked using gravimetric standards. The Standards are prepared between 50 and 4000 ppm WT. The linear correlation of 0.9999 indicates a linear behavior over 3 orders of magnitude The use of Deans configuration in combination with selected optimized stationary phases...