Table 2: Comparison of the main advantages and disadvantages of different flow formats for use in enzyme kinetics studies.

Flow formatsAdvantagesDisadvantages

Continuous flow(i) The most simple system because of no requirement of extra part or flow manipulation(i) Potential for low accuracy due to dispersion, dilution, and laminar flow effect (though, reports showed there are no significant problems)
(ii) High sample throughput with the least time consumption on flow operation(ii) May be lower in sensitivity than other formats, if not enough reaction time due to high flow rate

Stopped flow(i) Improved sensitivity by increasing reaction time before detection(i) Excessive stopped time may cause more dilution/dispersion of the reaction zone which will affect accuracy of the measurement
(ii) Possible to follow the reaction at various increments of stopped time which may give more information about the reaction(ii) Lower sample throughput because of longer analysis time due to the stopped time prior to detection

Quench flowSame as stopped flow format(i) Extra time consumption in collecting aliquots of quenched solutions for further analysis
(ii) The least automatic due to separated detection step
(iii) Requires quench solution to stop chemical reaction

Zone merging/bypass flow(i) Possible to calculate for accurate concentration of the detected product because only the part of the mixing zone that is not effected by dispersion/dilution is detected(i) Requires higher injected volume to gain adequate size of the product zone
(ii) More complicated arrangement, requires extra switching valve to change flow direction of the beginning and the end parts of the mixing zone, and needs precise time controlled operation

Air segmented flow(i) Accurate concentration because there is no dispersion, dilution, and or laminar flow effect on concentration measurement(i) Requires SIA system to precisely control small volume air segment which may not be possible if use FIA system
(ii) Ensures measurement of initial rate