Abstract: The invention relates to a gas chromatographic system (1000) for detecting volatile organic compounds in an analyte (320) with a gas chromatograph (100) having an injector for injecting analyte (320), a pre-concentrator (120), a column (140) equipped with a stationary phase (141) and a gas detector (150) configured to detect the analyte (320) component eluted from the column (140). The invention suggests an aggregate (160) having an outlet coupled to the gas chromatograph (100) and being configured to receive and process a hydrogen containing medium (330) for generating hydrogen (310) and supplying the hydrogen (310) to the gas chromatograph (100). The invention further relates to such an aggregate (160) and to a method of operating such a chromatographic system.