An in situ sampling device for capturing a material sample from a vessel. Embodiments of the present invention may be disposed as elongate probes having extendable sample capture elements. A sample capture element of such a device may include a concave sample capture pocket located near a distal end thereof. The sample capture pocket is adapted to capture a known volume of material when the sample capture element is extended into said material. The material sample remains trapped in the sample capture pocket upon sample capture element retraction. The sample capture pocket may be provided with a port for receiving material therein and a port for expelling material therefrom. These ports may be placed in communication with corresponding material transfer channels extending through the sample capture element. A device of the present invention provides for substantially contemporaneous sample capture and sample processing.