Stopped-Flow
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The Olis Advantage: Stopped-Flow

For over 20 years, Dr. Richard J. DeSa and company have computerized hundreds of stopped-flows, ranging from the most ambitious commercial models to simple homemade versions.

When we decided to make our own stopped-flow, we were unprejudiced in our selection of ‘best design features.’ We evaluated all innovations and chose the better design in every instance

“It had been around fifteen years since I did stopped-flow. I was comfortable with the Olis in about an hour [working solo on a colleague’s instrument]. The first shot filled the tubing. The second shot gave me partial kinetics. The third was the keeper. And the fourth shot confirmed the third. All in all, I used about 500 ul of solution.”

—Michael J. Barber, Ph.D., USF

We are the only stopped-flow manufacturer who uses ceramic valves; we chose them because ceramic is inert, impervious to temperature extremes, and very hard (99% the hardness of diamonds). We also offer the only stopped-flow with a safety interlock system that provides 100% assurance against misfiring.

Key Features of the U.S.A. Stopped-Flow

Deadtime: 1-2 ms for absorbance and fluorescence (5-10 ms for CD)

Valves: Fired Sapphire, low Volume Design (40-70 µl/syringe)

Mixer: Berger–Ball

Pathlengths available: 20 mm, 10 mm, 4 mm; and (for CD) 2 mm

Average Reagent Volume: 70-120 µl/syringe;

100% assurance against misfiring or pre-mixing, by means of 5 sensors producing a fail-safe interlock system

Drive syringes: SGE® glass syringes; low-temperature syringes also available

Tubing from valves to observation cell: Tefzel®, surgical stainless steel, or Teflon®

Syringe extenders: PEEK® (polyetheretherketone)

Observation chamber: quartz for absorbance and fluorescence models, stainless steel for low-temperature model.

Large, convenient, indestructible knobs and dials

Accessible ports with easy on/off fitting of water and gas lines to bath chamber for thermostatting and degassing of bath fluid and exposed syringe plungers.

Floodable water bath chamber made of Delrin®

Pneumatic drive system: one plunger moves both syringe pistons simultaneously.

Independent movement of syringes and valves for convenience in filling and flushing.

Anodized cast-aluminum channel (0.5 cm thick) and optical railing (1 cm thick) for high structural integrity

Weight: 18.6 pounds (8.45 kg)

Perfect, tool-free alignment of stopped-flow observation ports within sample compartment of host spectrometer.

TEFLON®, Tefzel®, and DELRIN® are registered trademarks of E.I. duPont de Nemours & Company.
UNIMETRICS® is a registered trademark of Unimetrics Corporation.
PEEK® is a registered trademark of Victrex PLC.

Compare Types

Primary Application: Absorbance and fluorescence ambient temperature

Temperature Range: -4°C to 40°C

Optical pathlength: 20mm for absorbance, 2mm for fluorescence

Optical Aperture size: 2mm for absorbance, 10 mm for fluorescence

Valve material: Ceramic

Flow Tube material: Suprasil (UV enhanced fused-silica)

Drive Syringe orientation: horizontal

 Reagent ratio supported: 1:1

Mixer: Ball-Berger

Drive mechanism: pneumatic

Primary Application: Absorbance at low temperatures

Temperature Range: -30°C to ambient

Optical pathlength: 10mm

Optical Aperture size: 2mm

Valve material: Ceramic

Flow Tube material: Stainless steel

Drive Syringe orientation: horizontal

 Reagent ratios supported: 1:1 – 1:10 as determined by syringe sizes

Mixer: Ball-Berger

Drive mechanism: pneumatic

Primary Application: Fluorescence

Other supported applications: Absorbance low temperature

Temperature Range: -4°C to 40°C

Optical pathlength: 4mm for absorbance, 4mm for fluorescence

Optical Aperture size: 2.4mm x 3.2mm (rectangular)

Valve material: Ceramic

Flow Tube material: Suprasil (UV enhanced fused-silica)

Drive Syringe orientation: horizontal

 Reagent ratios supported: 1:1 – 1:10 as determined by syringe sizes

Mixer: Ball-Berger

Drive mechanism: pneumatic

Primary Application: CD

Other supported applications: Absorbance low temperature

Temperature Range: -4°C to 40°C

Optical pathlength: 2mm for absorbance, 2mm for CD

Optical Aperture size: 6mm for absorbance

Valve material: Ceramic

Flow Tube material: Suprasil (UV enhanced fused-silica)

Drive Syringe orientation: horizontal

 Reagent ratios supported: 1:1 – 1:10 as determined by syringe sizes

Mixer: Ball-Berger

Drive mechanism: pneumatic

Olis Exclusively Offers Ceramic Valves
One-piece ceramic valves are used in all Olis stopped-flows. Ceramic valves are leak proof, inert, anaerobic, and impervious to temperature. The two valves are shown as they are positioned inside the cell assemblies.

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