Stopped Flow Cell

Stopped Flow Cell

These Stopped-Flow mixers for use with spectrophotometers are for the rapid preparation of reactive solutions. The assemblies are designed with mounts for absorbance, fluorescence and circular dichroism. These mounts also allow the mixers to be used with most spectrophotometers.

Item# Description U.S. List Price Quantity
72-6800 Ball Berger Mixer Only
72-6799 Low Temperature CD
72-6798 Low Temperature Fluoresence
72-6797 Low Temperature Absorbance
72-6796 Classic Ambient Temperature
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• Ideal for stopped-flow kinetics applications
• For use with any Pump Type
• Low volume design
• Low 1 to 5 msec dead time
• Ceramic valves
• Safety interlock system for 100% assurance against misfiring
These Stopped-Flow mixers for use with spectrophotometers are for the rapid preparation of reactive solutions. The assemblies are designed with mounts for absorbance, fluorescence and circular dichroism. These mounts also allow the mixers to be used with most spectrophotometers.
These Stopped-Flow Cell Assemblies include many key features, including a 1 to 2 msec dead time for absorbance and fluorescence and 3 to 5 msec for circular dichroism. The low volume design supports volumes of 40 to 70 µl/syringe/shot, compared to the average reagent volume of 70 to 120 µl. The drive syringes are SGE® glass, and low-temperature syringes are also available. The valves are made of fired sapphire ceramic which are inert, impervious to temperature extremes, and very hard. All Mixers are Ball-Berger, with pneumatic drive mechanism and horizontal drive syringe orientation. All mixers support reagent ratios of 1:1 to 1:10 as determined by syringe sizes.
The four Stopped-Flow Mixers are identical except for their sample cell assemblies. Please choose your mixer based on intended application use.
Classic Ambient Temperature Cell Assembly
The Classic Stopped-Flow Cell Assembly supports both absorbance and fluorescence measurements at moderate temperatures; because PTFE™ is used in the cell, temperatures below approximately 10°C are impractical. For fluorescence measurements, a mirror attachment is available to maximize emission collection. The mirror attachment slides over the cell assembly such that the mirror is positioned directly behind the rear window; emissions that would be lost through the rear window are thereby reflected towards the detector. The 20 mm quartz flow tube is mounted between a pair of PTFE™ end caps. A quartz window is installed in the end of each cap. Mixed reagents enter and exit the flow tube through the small holes in the end caps.
Low-Temperature Absorbance Cell Assembly
The Low-Temperature Absorbance Cell Assembly is one of two stopped-flows optimized for low-temperature experiments. This low-temperature absorbance stopped-flow has a stainless steel flow cell assembly with a 10 mm optical path length. The flow path is drilled directly through a solid block of stainless steel.
Low-Temperature Fluorescence Cell Assembly
The Fluorescence-optimized Stopped-Flow Cell Assembly supports absorbance measurements with a short path length. Like the Classic Absorbance/Fluorescence Cell Assembly, the Fluorescence-optimized Cell Assembly has an upper temperature limit of 80°C. This stopped-flow cell assembly uses a 4 mm flow cell made of Suprasil (UV-optimized fused silica).
Circular Dichroism with Stopped-Flow
Combining Circular Dichroism (CD) with stopped-flow speed mixing means detecting milliabsorbance signals on a millisecond time scale. Rendering this difficult measurement more practical is the CD Stopped-Flow Spectrophotometer. Fixed wavelength detection, recommended for all the more difficult measurements including UV readings, is done by sampling 1,000 times per second. With this millisecond detection rate, one can obtain excellent kinetic traces and calculate rate constants. Rapid-scanning detection, suitable for all of the easier measurements, including visible readings, can be done by sampling at rates to 62 CD scans per second. With this millisecond spectral detection rate, one can obtain kinetics at hundreds of wavelengths, supporting not only rate constant calculation but also spectral reconstruction.
Specifications72-680072-679972-679872-679772-6796
Flow Tube MaterialNASuprasil (UV-enhanced fused silica)Suprasil (UV-enhanced fused silica)Stainless SteelSuprasil (UV-enhanced fused silica)
Optical Aperature SizeNA6 mm2.4 mm x 3.2 mm rectangular2 mm2 mm for absorbance; 10 mm for florescence
Optical PathlengthNA2 mm for CD; 2 mm for absorbance4 mm for florescence; 4 mm for absorbance10 mm20 mm for absorbance; 2 mm for florescence
Other Supported ApplicationsNAAbsorbance Low TemperatureAbsorbance Low TemperatureNANA
Primary ApplicationsNACD Low TemperatureFluorescence Low TemperatureAbsorbance Low TemperatureAbsorbance and Fluorenscence Ambient Temperature
Temperature RangeNA-30 to 100-30 to 100-30 to 10010 to 80
Valve MaterialNAceramicceramicceramicceramic