a receptacle for use in collecting samples down a well bore is provided , the receptacle comprising a plurality of interconnecting modules . a main chamber is capable of holding a sample , and sensors within the chamber detect physical and chemical characteristics of the sample . valves in a chamber wall seal the chamber after a fluid sample has been collected . a communication means is placed in communication with the chamber so as to provide an externally accessible port which communicates with the inside of the chamber and allows detection and analysis of sample characteristics without removing the sample from the sealed chamber . the chamber includes a piston which is adjustable to keep pressure constant in the chamber and a heating element to keep temperature constant . a method for sampling downhole fluids is also provided .