Heart-Cut Two-Dimensional Countercurrent Chromatography with a Single Instrument

Abstract

Countercurrent chromatography (CCC) is a separation technique based on the liquid-liquid partitioning of compounds between the two phases of a biphasic solvent system. Limitations in the separation efficiency and peak capacity of one-dimensional (1D) CCC often result in insufficiently resolved peaks. Therefore, partially resolved peak fractions have to be rechromatographed in order to improve the yield and purity. Additional solvent evaporation steps can be circumvented by the application of two-dimensional CCC (2D CCC). Existing 2D CCC configurations are based on the linking of two CCC instruments which are not readily available in every laboratory. In this study, we introduce a technical improvement which allows performing multiple heart-cuts and 2D CCC separations with one instrument which has up to four independent coils, one pump, and one detector. For this purpose, we modified a commercially available CCC system by the addition of three six-port selection valves and a T-piece. The applicability of the 2D CCC system was shown under overloading conditions with eight alkyl hydroxybenzoates with nonideal conditions. We used two solvent systems which were hydrodynamically compatible and which showed different selectively characteristics with regard to the compounds. Four unresolved compounds in the first dimension were baseline resolved by means of the heart-cut technique, in which between 4 and 9 mL of the flow from coil 1 was transferred to coil 2. Three successive heart-cuts were performed that led to baseline resolution of unresolved compounds in the first dimension. The obtained recovery rates were 94-100%, and the purities of the compounds as determined by GC/MS were 90-100%.

Countercurrent chromatographic isolation and purification of 11′-α-tocomonoenol from the vitamin E extract of palm oil

“…Separations were performed with a Quickprep MK8 system (AECS Downend, UK) equipped with four separable coils (each about 120 mL) which were located in two different bobbins [20]. A perfectly balanced system was obtained by using two coils (2.1 mm internal diameter stainless steel tubing) located in different bobbins, namely coil 2 (122 mL) in bobbin 1 and coil 3 (114 ml) in bobbin 2, which were connected with PTFE tubing, resulting in a total volume of 236 mL.…”

Heart‐Cut Two‐Dimensional Countercurrent Chromatography for the Isolation of a Furan Fatty Acid Triacylglycerol from Latex Gloves and Identification of Further Lipid Compounds

“…All CCC separations were performed with an AECS Quikprep MK8 instrument (Downend, UK) using the peripherals described by Englert et al (, ). The CCC system consisted of a ternary beta 50 pump, a flash 10 DAD UV detector (wavelength 230 nm was used), a spider 06 mixing unit (all Ecom, Praha, Czech Republic), and a 203B fraction collector (Gilson, Middleton, WI, USA).…”

Poster „Aktuelle Themen aus Wissenschaft, Wirtschaft, Recht und Überwachung”

“…Jedoch wurden in den letzten Jahren auch apparative Methoden, wie Recycling-CCC oder Dual-Mode-CCC entwickelt, bei denen die Analyten jeweils mehrfach die CCC-Spule passieren [3]. Eine weitere Möglichkeit koeluierende Analyten voneinander zu trennen, bietet die zweidimensionale CCC mit Hilfe der Heart-cut-Technik [4]. Hierbei wird ein frei wählbarer Ausschnitt des Laufs mit koeluierenden Analyten in eine zweite Dimension ( bei der CCC ein zweites Coil ) übertragen, in der dann eine weitere Trennung stattfindet [5].…”

“…Die Analytik erfolgt mittels umfassender zweidimensionaler Gaschromatographie ( GC × GC ) in Kopplung mit einem Time-of-Flight-Massenspektrometer ( TOF-MS ) nach vorausgehender HS-SPME. Die Leistungsfähigkeit dieser modernen Analysetechnik konnte bereits anhand unterschiedlicher Weinsorten in Non-Target-Screenings demonstriert werden [4][5][6].…”