A system for desorbing and detecting an analyte sorbed on a solid phase microextraction (SPME) device, the system comprising: a SPME device; a desorption chamber (10; 20; 30) sized to accept the SPME device while defining a void volume of less than 50 μL; a flow injector in fluid connection with the desorption chamber, the desorption chamber and the flow injector being fluidly connected by at least a flow-insulating fluid connector (12; 22); a solvent source in fluid connection with the flow injector, optionally wherein the solvent source is fluidly connected with the flow injector at least through a pump capable of applying a pressure to the solvent to transfer the solvent to the flow injector; a detection device in fluid connection with the flow injector; and a fluid switch that: (a) in a desorption position, allows the solvent to be sprayed from the flow injector while flow-insulating any desorption solution in the desorption chamber, and (b) in a detecting position, isolates the solvent source from the flow injector by turning off the solvent flow while maintaining the fluid connection between the flow injector and the desorption chamber so as to transfer desorption solution in the desorption chamber through the flow-insulating fluid connector to the flow injector as an undiluted plug of liquid, and so as to spray the desorption solution from the flow injector into the detection device; optionally comprising a gas source for nebulizing solvent flowing from the flow injector; optionally comprising an agitator to vibrate an accepted SPME device, a heater to heat the desorption chamber, or both; the flow-insulating fluid connector (12; 22) is dimensioned to reduce or avoid diffusion of desorption solution from the desorption chamber (10; 20; 30) to the solvent flowing to the flow injector when (a) the fluid switch is in the desorption position, and (b) the solvent flows from the solvent source to the flow injector, wherein each of the desorption chamber and fluid connector are cylindrical; and wherein the flow-insulatinq fluid connector is dimensioned: (i) to have a smaller cross-section than a cross-section of the desorption chamber (ii) to be long in comparison with its cross-section such that solvent flowing past one end of the flow-insulating fluid connector does not affect desorption solution at the other end of the flow-insulating fluid connector; or (iii) both (i) and (ii). a SPME device; a desorption chamber (10; 20; 30) sized to accept the SPME device while defining a void volume of less than 50 μL; a flow injector in fluid connection with the desorption chamber, the desorption chamber and the flow injector being fluidly connected by at least a flow-insulating fluid connector (12; 22); a solvent source in fluid connection with the flow injector, optionally wherein the solvent source is fluidly connected with the flow injector at least through a pump capable of applying a pressure to the solvent to transfer the solvent to the flow injector; a detection device in fluid connection with the flow injector; and a fluid switch that: (a) in a desorption position, allows the solvent to be sprayed from the flow injector while flow-insulating any desorption solution in the desorption chamber, and (b) in a detecting position, isolates the solvent source from the flow injector by turning off the solvent flow while maintaining the fluid connection between the flow injector and the desorption chamber so as to transfer desorption solution in the desorption chamber through the flow-insulating fluid connector to the flow injector as an undiluted plug of liquid, and so as to spray the desorption solution from the flow injector into the detection device; (a) in a desorption position, allows the solvent to be sprayed from the flow injector while flow-insulating any desorption solution in the desorption chamber, and (b) in a detecting position, isolates the solvent source from the flow injector by turning off the solvent flow while maintaining the fluid connection between the flow injector and the desorption chamber so as to transfer desorption solution in the desorption chamber through the flow-insulating fluid connector to the flow injector as an undiluted plug of liquid, and so as to spray the desorption solution from the flow injector into the detection device; optionally comprising a gas source for nebulizing solvent flowing from the flow injector; optionally comprising an agitator to vibrate an accepted SPME device, a heater to heat the desorption chamber, or both; the flow-insulating fluid connector (12; 22) is dimensioned to reduce or avoid diffusion of desorption solution from the desorption chamber (10; 20; 30) to the solvent flowing to the flow injector when (a) the fluid switch is in the desorption position, and (b) the solvent flows from the solvent source to the flow injector, wherein each of the desorption chamber and fluid connector are cylindrical; and wherein the flow-insulatinq fluid connector is dimensioned: (i) to have a smaller cross-section than a cross-section of the desorption chamber (ii) to be long in comparison with its cross-section such that solvent flowing past one end of the flow-insulating fluid connector does not affect desorption solution at the other end of the flow-insulating fluid connector; or (iii) both (i) and (ii). (i) to have a smaller cross-section than a cross-section of the desorption chamber (ii) to be long in comparison with its cross-section such that solvent flowing past one end of the flow-insulating fluid connector does not affect desorption solution at the other end of the flow-insulating fluid connector; or (iii) both (i) and (ii).