Automatic solid Phase Microextraction (Spme) Sampling Apparatus

An automatic solid-phase microextraction apparatus using a probe comprising a fiber arranged slidingly inside a needle so such that it can be exposed to an environment from which to absorb an analyte of interest and then inside a gas chromatographic injector for the desorption of the analyte, the apparatus comprising an arm movable according to a pre-established program, with a head carrying a substantially tubular holder with a chamber for the probe and a plunger in the holder for actuating the protrusion and withdrawal of at least a portion of the fiber, the apparatus also comprising a storage unit of test tubes containing samples to analyze and/or probes with already-exposed fibers, and optionally also fibers that have yet to be exposed, accessible to the movable arm, the apparatus being characterized in that:

• one end of the fiber in the probe is fitted with a connection element made of a ferromagnetic material and the end of the needle wherein the fiber is engaged has a ferromagnetic flange;
• the plunger in the holder has at least one magnet at the end interacting with the fiber, and one or more further magnets provided at the free end of the holder;
• the head comprises at least a guide block for slidingly housing the needle when the probe is engaged in the holder, the guide block being arranged underneath the free end of the holder and fitted with at least one magnet at its lower end;
• there is provided an intermediate transfer bracket accessible to the mobile arm and suitable for vertically supporting one probe, and comprising a device for engaging the ferromagnetic connector on the fiber and the ferromagnetic flange on the needle;
• the head of the movable arm being suitable for collecting the probe according to a first collection mode, by bringing the end of the guide block up against the ferromagnetic connector on the fiber, or according to a second collection mode, by bringing the end of the plunger and the free end of the holder respectively up against the connector on the fiber and the flange on the needle, whereby the probe is placed inside the chamber of the holder with the needle extending axially therefrom;
• the first collection mode being used to transfer the probe from the storage unit to the intermediate transfer bracket and vice versa, while the second collection mode is used to transfer the probe from the intermediate transfer bracket to the gas chromatograph injector or to the storage unit to absorb an analyte, as a result of corresponding movements of the mobile arm.