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Modification of the Carlo-Erba cold on-column injector for (automated) analysis of high molecular compounds at high oven temperatures is described. The secondary cooling tube of the cold on-column injector is replaced by a lengthened tube through which a high air flow is directed. The injection site is maintained at 65-70°C while the oven is at high temperature (Z 3OOOC). For automated injection, a short deactivated precolumn of 22 to 30 cm X 0.53 mm i.d. is coupled to the analytical column via a butt connector with make-up gas supply. For a triglyceride mixture, automatically injected at 300°C, the mean %deviation forall peakareaswas 1.8%and themean%deviation for all retention times was 0.09% for five consecutive runs.

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In this study, the cold split-splitless injector recently introduced by Carlo Erba was optimized for the trace analysis of polycyclic aromatic hydrocarbons. Injections of hundreds of microliters of hexanesolutions were performed in the solvent split mode using an autosampler programmed for large volume injection. Injection parameters such as type of insert, initial oven temperature, split time, and flow are shown to play important roles in defining the conditions for obtaining quantitative results. The loss of early elutingcompoundscan be minimized by achieving a solvent trapping effect, making use of n-octaneas co-solvent in n-hexane.