Journal of Chromatography A, 1023 (2004) 165–174 AT-column, a novel concentrating technique for large-volume injections in gas chromatography Sjaak de Koning a,∗ , Mitsuhiro Kurano b , Hans-Gerd Janssen c , Udo A.Th. Brinkman d a ATAS GL International, P.O. Box 17, 5500AA Veldhoven, The Netherlands b GL Sciences, 237-2 Sayamagahara, Iruma, Saitama 358-0032, Japan c Central Analytical Sciences, Unilever Research & Development Vlaardingen, P.O. Box 114, 3130AC Vlaardingen, The Netherlands d Department of Analytical Chemistry and Applied Spectroscopy, Free University, De Boelelaan 1083, 1081HV Amsterdam, The Netherlands Received 5 August 2003; received in revised form 7 October 2003; accepted 13 October 2003 Abstract Nowadays, large-volume injection is widely used for the GC determination of trace analytes, specifically to improve detectability. The most popular injectors for large-volume injections are the programmable temperature vaporisation (PTV) injector and the cold on-column (COC) injector, where each device has its own advantages and limitations. The novel AT-column concentrating technique combines features of two other injection techniques, loop-type large-volume and vapour overflow. AT-column injection is based on solvent evaporation in an empty liner with solvent vapour discharge via the split line. Little or no optimisation is required. The only relevant parameter is the injection temperature which can easily be calculated using the equation of Antoine. As an application, AT-column injection is combined with GC–MS for the trace-level determination of labile analytes and with GC–flame ionisation detection for the analysis of high molecular weight polymer additives. In summary, AT-column is an injection technique that combines the inertness of the COC, and the flexibility and robustness of the PTV large-volume technique. © 2003 Elsevier B.V. All rights reserved. Keywords: Large-volume injections; AT-column injection; Programmed-temperature vaporiser; Injection methods; Instrumentation; Alkanes; Dichloromethane; Acetonitrile; Methyl acetate 1. Introduction In recent years, many studies were reported in which large-volume injection (LVI) methods were efficiently used for the GC determination of trace-level analytes. The major advantage of LVI techniques is that a much better ana- lyte detectability can be obtained. Instead of the maximum volume of about 2 l that can be injected when using a conventional technique such as splitless injection, with LVI injection volumes of 50–100 l can easily be used [1,2]. Alternatively, if the improved detectability is not, or only partially required, sample preparation can be simplified by omitting time-consuming solvent evaporation steps which, in addition, often cause analyte losses. Typical LVI injec- tors are the programmable temperature vaporiser (PTV) ∗ Corresponding author. Present address: Leco Instrumente GmbH, Seperation Science Group, Marie-Bernays-Ring 31, Mönchengladbach 41199, Germany. E-mail address: sjaak.dekoning@leco.de (S. de Koning). [3,4] and the cold on-column (COC) injector [4–7]. In the PTV technique, the injector contains a liner packed with a sorbent to retain the large volume of solvent in the liner. When a PTV-type large-volume injection is performed, the injector temperature is set 10–40 ◦ C below the boiling point of the solvent. The large volume is rapidly injected into the injector in the split mode, thereby providing a high carrier gas flow rate. The solvent is evaporated and the solvent vapour is eliminated through the split line by the high flow of carrier gas, while the analytes are retained on the packing of the liner. After evaporation of the solvent, the injec- tor is switched to the splitless mode and the temperature is programmed to volatilise the analytes, which are then transferred to the capillary column. A disadvantage of PTV large-volume injection is that quite a few labile compounds are prone to decomposition due to catalytic effects of the packing material [8,9]. Moreover, heavy compounds are so strongly retained on the packing that desorption cannot be effected anymore. With the large-volume COC technique, a long pre-column is used to separate the sample solvent 0021-9673/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2003.10.031