A system comprising: a flow system including a pump system and a valve system, wherein the pump system and the valve system are in fluidic communication; a sampling system in fluidic communication with the flow system; a reactor comprising a fluid, wherein the sampling system is in fluidic communication with the reactor, wherein in a first configuration of the valve system the fluid sample is allowed to flow from the reactor to the pump system through the valve system at a first flow rate; and a sensor system in fluidic communication with the flow system, wherein in a second configuration of the valve system the fluid sample is allowed to flow from the pump system to the sensor system at a second flow rate, a mass exchanger (80, 200) in fluidic communication with the flow system and the sensor system, wherein the mass exchanger (80, 200) is configured to condition the fluid sample to produce a conditioned fluid sample for analysis by the sensor system, wherein the mass exchanger (80, 200) includes a first flow channel (202, 212, 222, 234) having a first flow channel entrance (202a, 212a, 222a, 234a) and a first flow channel exit (202b, 212b, 222b, 234b), and a second flow channel (204, 215, 224, 235) having a second flow channel entrance (204a, 215a, 224a, 235a) and a second flow channel exit (204b, 215b, 224b, 235b), wherein the first flow channel (202, 212, 222, 234) and the second flow channel (204, 215, 224, 235) are separated from one another by a selectively permeable membrane (206, 216, 226, 236), wherein the mass exchanger (80, 200) is configured to flow the fluid sample through the first flow channel (202, 212, 222, 234) from the first flow channel entrance (202a, 212a, 222a, 234a) to the first flow channel exit (202b, 212b, 222b, 234b) and be in fluid communication with the selectively permeable membrane (206, 216, 226, 236), and wherein the mass exchanger (80, 200) is configured to flow a conditioning fluid through the second flow channel (204, 215, 224, 235) from the second flow channel entrance (204a, 215a, 224a, 235a) to the second flow channel exit (204b, 215b, 224b, 235b) and be in fluid communication with the selectively permeable membrane (206, 216, 226, 236), wherein the sample fluid and the conditioning fluid are in communication through the selectively permeable membrane (206, 216, 226, 236), wherein the mass exchanger (80, 200) is configured so that the sample fluid is converted to a conditioned fluid sample through interaction of the sample fluid with the conditioning fluid and the selectively permeable membrane (206, 216, 226, 236), wherein the sensor system is configured to analyze the conditioned fluid sample. a flow system including a pump system and a valve system, wherein the pump system and the valve system are in fluidic communication; a sampling system in fluidic communication with the flow system; a reactor comprising a fluid, wherein the sampling system is in fluidic communication with the reactor, wherein in a first configuration of the valve system the fluid sample is allowed to flow from the reactor to the pump system through the valve system at a first flow rate; and a sensor system in fluidic communication with the flow system, wherein in a second configuration of the valve system the fluid sample is allowed to flow from the pump system to the sensor system at a second flow rate, a mass exchanger (80, 200) in fluidic communication with the flow system and the sensor system, wherein the mass exchanger (80, 200) is configured to condition the fluid sample to produce a conditioned fluid sample for analysis by the sensor system, wherein the mass exchanger (80, 200) includes a first flow channel (202, 212, 222, 234) having a first flow channel entrance (202a, 212a, 222a, 234a) and a first flow channel exit (202b, 212b, 222b, 234b), and a second flow channel (204, 215, 224, 235) having a second flow channel entrance (204a, 215a, 224a, 235a) and a second flow channel exit (204b, 215b, 224b, 235b), wherein the first flow channel (202, 212, 222, 234) and the second flow channel (204, 215, 224, 235) are separated from one another by a selectively permeable membrane (206, 216, 226, 236), wherein the mass exchanger (80, 200) is configured to flow the fluid sample through the first flow channel (202, 212, 222, 234) from the first flow channel entrance (202a, 212a, 222a, 234a) to the first flow channel exit (202b, 212b, 222b, 234b) and be in fluid communication with the selectively permeable membrane (206, 216, 226, 236), and wherein the mass exchanger (80, 200) is configured to flow a conditioning fluid through the second flow channel (204, 215, 224, 235) from the second flow channel entrance (204a, 215a, 224a, 235a) to the second flow channel exit (204b, 215b, 224b, 235b) and be in fluid communication with the selectively permeable membrane (206, 216, 226, 236), wherein the sample fluid and the conditioning fluid are in communication through the selectively permeable membrane (206, 216, 226, 236), wherein the mass exchanger (80, 200) is configured so that the sample fluid is converted to a conditioned fluid sample through interaction of the sample fluid with the conditioning fluid and the selectively permeable membrane (206, 216, 226, 236), wherein the sensor system is configured to analyze the conditioned fluid sample.