用于烯烃分析的SFC-FID的评估ASTM D6550方法

SFC已经使用ASTM D5186和D6550方法很好地用于汽油和柴油燃料分析。两种ASTM方法都需要二氧化硅柱进行分离，而D6550需要使用额外的银柱来保留烯烃。在先前的申请说明中，在不同的温度和背压下对各种二氧化硅柱进行了评估。使用最佳柱和操作条件来评估我们的SFC-FID满足ASTM D6550方法规范的能力。UASGOApplication Note 2/4Evaluation of the SFC-FID for the Olefin Analysis ASTM D6550 MethodApplication Note Evaluation of the SFC-FID for the Olefin Analysis ASTM D6550Method SFC has been well established for gasoline and diese l fuel analysis， using the ASTM D5186 a nd D6550 methods. Both ASTM methods require a silica column for the separation， while D6550req u ires the use of an additiona l silver column for retention of the o l efins. In previous application notes a variety of silica columns were evaluated at various temperatures and back pressures. T he best column a nd oper a ting conditions were used to evaluat e our SFC-FID ab i lity to meet the s p ecifications of the ASTM D6550 method. Keywords SFC， Gasoline ， Diesel， Sil i ca column， FID， Alkanes ，Aromatics， Pressure， Temperature， Density ASTM D5186 ASTM D6550 SFC-FID system Experimental Equipment： Conditions： CO2 Delivery Pump： PU-2080-CO2 Autosampler： XLC-3159AS Column oven： CO-2060 Fid DANI Oven-FID Back Pressure BP-2080 Injection Vol.： 0.5pL Silica Column： JASCO Silica 4.6x250mm， 5pm x2 Silver Column： JASCO Silver 4.6x50mm， 5pm CO2 Flow rate： 3.0 mL/min Column temp.： 35°C Back Pressure： 100 bar FID Splitter： 200°℃ FID Detector： 350°℃ The standards were purchased from Spectrum Quality Standards a n d consisted of individua l ampules of 1.0%，3.5%，6.0%，8.5%，12.0%，17.0% and 25.0% olef i n in a mixture of 75% isoocta n e ： 25% toluene. Fi g ure 1. ASTM D6550 Olefin Analysis. Sample is 25% olefins. Overlay o f 20 injections. The overlay of 20 chromatograms of the 25% olefin sample is shown in Figure 1. The zoomed olefin overlay of t hose 20 injec ti ons is shown in Figure 2. The overlay of t he olef i n peak of the various standards， 1.0%，3.5%， 6.0%，8.5%，12.0%，17.0% and 25%， is shown in figure 8 and t he corresponding calibration curve from those sta n dards is also shown. The linearity of the calibration curve had a correlation coefficient (R) of 0.997. Figure 2. Ove r lay of 1.0%， 3.5%， 6.0%，8.5%， 12%， 17%， and 25% Olefins. Calibration curve correlation coeff i cient (R) was 0.997. The overlay 20 in j ect i ons of 3.5% and 12% olefins with the zoom of just the olef i n is shown in Fig u re 3.Excelle n t retention t i me reproducibility (%RSD) was achieved of 0.092 for 3.5% and 0.143 for 12.0%. Fig u re 3. Overlay of 3.5% (left ) and 12% (right) Olefins. Retent i on t i me RSD of 0.092 and 0.143 for 3.5%and 12.0%， respectively. The ASTM method requires repeatability testing on one system by one use r and reproducibility testingon a different system by a different user . The repeatability is defined by the equation， repeatability=0.11 X0.75 and the reproducibility is defined by the equation， reproducibility= 0.47 X0.75， where in each X is between 1 and 25%mass % olefin. The tables below show the acceptable and measured repeatability and reproducibility for the entire olefin range. Table 1. ASTM D6550 Repeatabi l ity.Acceptance is determined for each % of olefin us i ng the equation，repeatability = 0.11 X0.75， and the measu r ed is calculated f rom the 20 i n j ections of each olefin standards. % Olefin Acceptance Measured 1.0 ±0.110 0.04 3.5 ±0.281 0.06 6.0 ±0.422 0.06 8.5 ±0.548 0.20 12.0 ±0.709 0.55 17.0 ±0.921 0.90 25.0 ±1.230 0.58 Table 2. ASTM D6550 Reproducibility. Acceptance i s determined for each % of olef i n using the equation，reproducibility= 0.47 X .75， and the measured is calculated from the 20 i njections of each olefin standards. %Olefin Acceptance Measured 1.0 ±0.470 0.10 3.5 ±1.203 0.16 6.0 ±1.802 0.34 8.5 ±2.340 0.38 12.0 ±3.030 0.44 17.0 ±3.935 1.05 25.0 ±5.255 1.63 As the results show in the repeatability and reproducibility tables， the SFC-F I D exceeds the requirements of the ASTM D6550. Having exceeded the acceptable values， the SFC-FID system can successfully be used for the automated analysis of olef i ns i n gasoline.