Journal of Chromatography A, 1101 (2006) 315–318 Short communication Sol–gel multicapillary columns for gas–solid chromatography Vladimir N. Sidelnikov a , Yuri V. Patrushev a , Yuri P. Belov b,∗ a The Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk, Russia b ChromBA, Inc., State College, PA, USA Received 22 July 2005; received in revised form 1 November 2005; accepted 7 November 2005 Abstract In this work, we report the method for the preparation of multicapillary columns (MCCs) for gas–solid chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol–gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by gas–solid chromatography. Nine-component mixtures of C1–C4 hydrocarbons are separated within 8–12 s. The efficiency of 25–30 cm long alumina sol–gel MCCs consisting of approximately 1400 capillaries of 40 m diameter is up to 2500–3000 theoretical plates. © 2005 Elsevier B.V. All rights reserved. Keywords: Multicapillary chromatography; Multicapillary GC; Gas–solid chromatography; High-speed GC; High-speed analysis of light hydrocarbons 1. Introduction Multicapillary columns (MCCs) are used in GC when higher speeds of separation are desired [1–3]. Commercial MCCs for GC are manufactured by coating the capillary walls with liq- uid stationary phases. Thus, these columns are intended for gas–liquid chromatography. Analytical problems exist where gas–solid chromatography is necessary for successful separa- tions. Typical examples include the analysis of permanent gases, light hydrocarbons, and volatile oxides. Conventional single capillary columns for gas–solid chro- matography can be prepared by deposition of solid adsorbent particles of 2–7 m diameter on the capillary walls from a sus- pension in an appropriate solvent [4,5]. These particles are small compared to the diameters of standard single capillary columns (200–530 m), but are relatively big as compared to the diame- ter of multicapillary columns (40 m). It is difficult to achieve a uniform coating of 40 m capillaries by deposition of 2–7 m diameter particles from a suspension. The capillaries are easily clogged. ∗ Corresponding author. Tel.: +1 814 867 4110. E-mail address: ybelov@chromba.com (Y.P. Belov). Based on sol–gel technology [6,7], we developed the method for preparation of MCCs for gas–solid chromatography. In this work, we prepared and evaluated MCCs with neat porous alu- mina and with alumina-organic hybrid adsorbents. 2. Experimental 2.1. Materials All reagents were of analytical grade. Polypropylene glycol (PPG) with an average molecular weight of 2025 (PPG-2025) was obtained from Merck. Water was distilled and deionized. Multicapillary glass tubes are available from ChromBA. In this work we used multicapillary tubes with the following charac- teristics: maximal outer cross section diameter: 2.3 mm; inner diameter of capillaries: 40 m; number of capillaries: approxi- mately 1400. 2.2. Methods To prepare a porous layer MCC for gas–solid chromatog- raphy, the capillaries were filled with an appropriate sol. The solvent was then removed from the capillaries, which resulted in the formation of a porous adsorbent layer on the capillary walls. 0021-9673/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2005.11.021