A fluid path set includes a first fluid line having a proximal end fluidly connectable to a source of a first fluid and a second fluid line having a proximal end fluidly connectable to a source of a second fluid. A flow mixing device is in fluid communication with distal ends of the first and second fluid lines. The flow mixing device includes a housing, a first fluid port provided for receiving the first fluid, and a second fluid port for receiving the second fluid. A mixing chamber is disposed within the housing and is in fluid communication with the first and second fluid ports. A third fluid port in fluid communication with the mixing chamber for discharging a mixed solution of the first and second fluids. A turbulent flow inducing member is disposed within the mixing chamber for promoting turbulent mixing of the first and second fluids.

Multiple-emulsion nucleic acid amplification allows nucleic acids contained in biological systems to be detected, quantitated and/or sorted based on their sequence as detected with nucleic acid amplification techniques, e.g., PCR. The nucleic acids can be free floating or contained within living or nonliving structures, including particles, viruses, and cells. The nucleic acids can include, e.g., DNA or RNA. Systems and devices for use in practicing methods of the disclosure are also provided.