Amounts of volatile organic compositions can be evaluated from vapor samples based on the time dependent response of a fuel cell contacted with the vapor sample at its anode. The actuation system includes a carriage which can move in each of two directions, a first pivoting part coupled to the first mold part, a second pivoting part coupled to the second mold part, and at least one actuating member connected to each of the carriage and at least one of the first and second pivoting parts. The word line driver is electrically coupled to the memory array by a plurality of word lines. In one preferred embodiment, multiple measurement cells are disposed along a transmission line.