二氧化硅柱在SFC分离中提高分辨率的评价

SFC已被很好地用于制药工业中的对映体分离和纯化，以及用于燃料分析、汽油和柴油，使用ASTM D5186和D6550方法。随着替代燃料的开发，将这些新的替代燃料与传统燃料进行比较的分析测试变得越来越重要。两种ASTM方法都使用硅柱进行分离，而D6550在烷烃和芳香烃分离后使用银柱来保留烯烃。我们在这个应用中的目标是通过评估各种硅柱来进一步优化ASTM方法，以最大限度地提高分离效率。本应用中结论：孔径是分离烷烃和芳烃的柱的分离效率的重要因素。JASCO 30A提供了十六烷、环己烷和甲苯的最佳分辨率， Princeton 30A提供的十六烷和环己烷的分辨率非常接近第二，但与JASCO二氧化硅的7.7相比，分辨率更低，为5.4。Application Note 2/4Evaluation of Silica Columns for Increased Resolution in SFC separations Evaluation of Silica Columns for Increased Resolution in SFC separations SFC has been wel l established for enantiomer i c separat i ons and purificat i ons in the pharmaceutical indus t ry as well as for fue l analysis ， gasoline and diesel ， using the ASTM D5186 and D6550 m ethods.As alter n at i ve f u els are being developed， there is an increased importance on the analy t ica l testing for comparing these new alternatives to the tradit i onal fue l s . Both ASTM methods use a silica column for the separation， wh i le D6550 second a r i ly employs a silver column for retent i on of the olefins after the alkanes and aromatics are separated. Our goal in this applica t ion is to further opt i mize the ASTM methods by evalua t i ng a variety of sil i ca col u m ns to maximize the separation ef f iciency. Keywords： SFC， Ga so l i n e ， D ie s e l ， S i l i c a c o l um n ，F I D ， Al k a n e s， Ar o m a t ic s， H I L I C Application Note Exp e r ime nta l Equipment Conditions CO2 Delivery Pump： PU-2080-CO2 Autosampler： XLC-3159AS Column Oven： CO-2060 PDA Detector： MD-2018 (High pressure cell) FID： DANI Oven-FID Back PressureRegulator： BP-2080 Column： Various CO2 Flow rate： 2.0 mL/min 35°℃ Various Wavelength： 225 nm 200℃ Fi g u r e 1. Silica Col u mn Co m pariso n. Bac k Pr e ssure 120b ar.B l ue l ine =F I D， Pink lin e= UV a t 225n m. Peaks： 1. Hexadeca n e， 2. Cyc l ohexa ne ， 3. To luene ， 4. N a phtha l ene. Fi gure 1 shows t h e comparis o n of t h e 6 sili c a columns f rom var i ous m anufac t u re r s at 120 b ar back press u r e.T h e JASCO co l umn is the o n ly o n e t h at shows any separa t io n o f h e xadecane and cyclo h e xane a n d cl e a r ly shows the most reso luti on b etween t hose peaks and t he t oluene and nap h thalene pea k s. Figu r e 2 shows t his sa m e compa r ison at 200 ba r and a g a i n t he s epa rat i on of h exadecane and c yc lo h exane i s t h e bes t and t he r esolutio n betwee n those pea k s and to l ue n e and naphtha l ene is the la r gest. F ig u r e 2. Si l i ca Co l u mn Com p ar i so n. B ack Pressure 200bar.Blue l ine =FID， Pink l in e = U V at 225nm.Pea k s： 1. H exadeca n e， 2. Cyc l ohexa n e， 3. T olue n e， 4. Nap h t h alene. As t he P r i n ceton 60A and the JASCO co l umns were t he o n l y o n es to s h ow separa t io n o f hexadecane and cyclo h exane， those were fur t h er eva l u ated at a few othe r p ressures. As t h e reso l u tion of those peaks i nc r eased when r unning a t 200 b ar compared to 120ba r ， 150b ar a n d 250bar we r e r u n t o co n firm t he trend a n d a l so that higher pressure led t o t h e b est sepa r at i o n. F i gu re 3. P r ince t on a n d JASCO Silica Co l u mn Com p ar i so n. B l u e l ine =F I D ， Pink l in e = UV a t 225n m . P e a k s： 1. Hexad e ca n e， 2. Cyc l ohexa n e ， 3. T olue n e ， 4. N a p h t h a l e n e. As i llust r ated in f i gure 3， a n i nc rease i n p ressure l ed to be t te r r esolutio n and 250ba r was p rov e n to b e t he bes t back pressu r e o n bot h columns， wi t h t h e JASCO co l u mn proving to be t he bes t . As t he po r e s i ze of t h e JASCO column i s 30A， a Pri n ceto n 30A was compared as well as a P h enomenex K i n etex H I LI C column using a simpl if ied 3 compo n ent m i x. As s h ow n i n f igu r e 4 the di f ference betwee n the Pr inceton 30A and Pr inceton 60A i s signif i ca n t as t h e sepa r at i on of hexadecane and cyc l ohexane i s drastical l y i m p roved . T h e K in etexQ column did not s h o w m u c h re t ent i o n of any o f the p eaks. As th e p o re size was 100A tha t was l i k ely a fac t or i n t he insuf f icie n t reso luti on o f h e xadecane and c yclo h exane. Fi g ure 4. Silica Co l u mn Compar i son . Bac k P ressure 250bar.. Pea k s： 1. Hexadecan e ， 2. Cyc l ohexa n e 3. To l uene C on c lusi o n T h e p ore size i s a s i g n i f ica n t f a c tor in the sepa r ati o n eff i ci e nc y of t he c olumn f or the sepa r a t i o n a l k a nes and a r omati c s. The JASCO 30A prov i d e d t he b e st resolut i on of h e xa de ca n e ， cyc l ohexa n e a n d to l u e ne wi th t h e Pr i n ceto n 30A a ve r y c l ose 2nd prov i d i n g equa l resolut i on of hexad e ca n e and cyc l ohexa n e ， bu t l e ss resolut i on of 5.4 co m pared to 7.7 o n the Jasco si li ca .