An interchangeable preconcentrator assembly for delivering an analyte to an analysis instrument. The assembly includes a housing defining an inner chamber. An inlet is in fluid communication with the inner chamber, an outlet is in fluid communication with the inner chamber for delivering fluid to the inlet of the analysis instrument, and an exhaust outlet is in fluid communication with the inner chamber. A plurality of removable preconcentrator packages are disposed within the inner chamber. Each of the removable preconcentrator packages including a microscale preconcentrator. A fluid flow path is defined between the inlet and the inner chamber. A first fluid flow path is defined between the preconcentrators and the exhaust outlet, and a second fluid flow path is defined between the preconcentrators and the outlet. A selectably operable valve directs fluid flow from the inner chamber into either the first fluid flow path or the second fluid flow path.