Separation of benzene and deuterated benzenes by reversed-phase and recycle liquid chromatography using monolithic capillary columns

• Published in: Journal of separation science Vol. 27; no. 15-16; pp. 1339 - 1344
• Main Authors: Lim, Lee Wah, Uzu, Hideyuki, Takeuchi, Toyohide
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.11.2004; WILEY‐VCH Verlag; Wiley
• Subjects: Alternate-pumping; Analytical chemistry; Benzene; Chemistry; Chromatographic methods and physical methods associated with chromatography; Deuterated benzene; Exact sciences and technology; Monolithic silica capillary column; Other chromatographic methods; Recycle LC; Reversed-phase; Capillary column; Deuterium; Purification; Hydrocarbon; Reversed-phase; Monolithic column; Number of theoretical plates; Liquid chromatography; Hydrogen Isotopes; Silica; Optimization; Microbore column; Deuterated benzene; Reversed phase chromatography; Plate efficiency; Benzene; Recycle LC; Alternate-pumping; Recycling; Monolithic silica capillary column; Labelled compound
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.200401882

An alternate pumping‐recycle system utilizing a commercially available low dead‐volume switching valve was developed for microcolumn LC. The recycle system had two separation columns, and the dead volume of the recycling lines was kept to a minimum by avoiding passage of the sample through the pump chamber, sample injector, and the normal path length of a conventional UV detector. The drawback of the high total back pressure caused by the second column that is placed after the detector was overcome by on‐column detection, and this eliminated the need for a high pressure flow cell. The system was used for the separation of an authentic mixture of benzene, benzene‐1,3,5‐d3, and benzene‐d6. Baseline separation was accomplished after six cycles and the calculated theoretical plate number for benzene was 230,000. It was observed that the theoretical plate number (N) increased linearly with increasing number of cycles, and the N per unit time increased with increasing inlet pressure. The separation conditions were optimized and the separation of benzene and benzene‐d6 was accomplished within 75 min at 2.5 MPa inlet pressure.