Fused silica capillaries (Polymicro Technologies, Phoenix, AZ, USA) with dimensions 48.5-cm total length, 40-cm effective length, 75-μm i.d., and 375-μm o.d. were used.
Fused silica capillaries (PolymicroTechnologies, Phoenix, AZ, USA) with dimensions48.5-cm total length, 40-cm effective length, 75-μm i.d.,and 375-μm o.d. were used.