An interchangeable preconcentrator assembly comprises an outer housing and an inner housing defining a chamber. A biased urging member is held at least partially within the outer housing and slidably biased toward a surface of the inner housing. When the biased urging member is at least partially retracted, a space is defined between the urging member and the surface of the inner housing for accommodating at least one preconcentrator chip. A continuous fluid flow path is defined through the outer housing and through the space. The interchangeable preconcentrator assembly may further comprise at least one modular preconcentrator carriage.