An automated glass capillary gas chromatographic system for routine quantitative analysis

A steel capillary gas chromatographic system, based on the Hewlett-Packard (HP) Model 5711A gas chromatograph and HP model 3354A laboratory data system, was converted to an automated glass capillary system suitable for routine quantitative analysis of trace levels of hydrocarbons. Two instrument modifications, which were required for a fully automated system, are described. The system was tested with two different column installation methods. The HP recommended method of column installation showed much less discrimination against high molecular weight compounds than did a simpler column installation technique that introduced excessive dead volume (unswept by the carrier gas) into the HP Model 18740A glass capillary inlet system. Discrimination against high molecular weight compounds was shown to adversely affect their quantification. Data on the accuracy and precision of quantitative analyses of 18 hydrocarbons covering a wide range of boiling points and polarities are presented for both column installation techniques. Retention time reproducibiiity data for the same 18 compounds are also included.