Rapid Mixing Accessory

Product Codes: SFA-20 & SFA-20mx

The SFA-20 rapid mixing accessory has remained a popular choice for users who want to add a stopped-flow capability or simply a means of rapidly mixing reagents in the context of a commercial UV/Vis or fluorescence instrument. It may be adopted as an entry level stopped-flow device but is capable of producing results for genuine research applications.

It has a nominal deadtime < 8ms, allowing reaction rates of up to 100 s-1 to be monitored, depending on the response time of the spectrometer.

High precision, research grade, gas-tight syringes are used and are available in volumes from 250 µl to 5 ml. Variable ratio mixing applications are readily accommodated since the syringes are mounted outside the thermostatically controlled sample circuit, allowing easy and rapid replacement. This also prevents any possibility of leaks at low temperatures.

The syringes are mounted on a rigid drive platform ensuring that the flow is stopped precisely and instantaneously. This platform and the syringe mounting blocks are extremely resistant to chemical attack. The thermostatted sample circuit itself is constructed from materials which also provide optimum chemical resistance. Reagents travel in this inert sample circuit through an umbilical cord to the flow cell where they are mixed by a high efficiency T-format mixer.

The cell offers both 2 mm and 10 mm optical path lengths as standard. The standard flow cell supplied with the SFA-20 Series will fit any UV/Visible spectrophotometer or spectrofluorimeter having standard 1 cm cuvette holder and a 15 mm beam height. However, flow cells can be tailored for instruments with different beam height and optical geometry.

Options for the SFA-20 series include:

  1. An anaerobic kit to extend the use of the SFA-20 to applications where oxygen must be excluded.
  2. A pneumatic drive attachment for enhanced shot-to-shot reproducibility.
  3. A range of different size drive syringes for variable ratio mixing.

Rapid Kinetic Accessory – Microvolume Version

Product Code: SFA-20M
The SFA-20M is a microvolume version of the standard accessory. With a dead volume of just 350 µl per reagent, it is ideally suited to leading edge research where only small quantities of novel or expensive materials are available.

Rapid Kinetic Accessory – Multi-mixing Version

Product Code: SFA-20mx
The SFA-20mx incorporates two mixers separated by a 10 µl delay loop. This enables two reagents to be mixed prior to a third reagent being introduced and mixed immediately before the observation chamber. It can also be used for single mixing and 2:1 ratio single mixing without the need to change syringes.

Rapid Kinetic Accessory – Microvolume Multi-mixing Version

Product Code: SFA-20mxM
The SFA-20mxM combines the benefits of microvolume operation with multi-mixing capabilities.

Optimized Versions and OEM Partners

The SFA-20 accessory can be used on a wide range of spectrophotometers and fluorimeters e.g. Agilent (Hewlett Packard), Edinburgh Instruments, Hitachi, Horiba, Perkin Elmer, PTI, Shimadzu, Kontron, ISS etc.  Check with TgK Scientific for compatibility with your instrument.  Some of these have justified some optimisation or adaption for certain configurations:

  1. SFA-20/ HITACHI Rapid Kinetics Accessory optimised for use with Hitachi Fluorimeter
  2. SFA-20/ PERKINELMER Rapid Kinetics Accessory optimised for use with Perkin Elmer Fluorimeters
  3. SFA-20/ VARIAN Rapid Kinetics Accessory optimised for use with Agilent Cary instruments
  4. SFA-20/ BECKMAN Rapid Kinetics Accessory optimised for use with Beckman DU 7000 Series
  5. SFA-20/ SPEX Rapid Kinetics Accessory optimised for use with HoribaJY FluoroLog and FluoroMax
  6. Edinburgh Instruments integrate the SFA20 in to their FLS1000, FS5 and LP980 instruments.

Note: Multi-Mixing and Micro-volume versions of the above are available on request.


Special versions of the SFA-20 are available on request.

    Relevant Application Notes

  • AN.002.S20

    Evaluation of rapid kinetics data from a vertical beam commercial spectrofluorimeter using an optimised SFA-20/PerkinElmer stopped-flow accessory

    1. Stopped-flow accessory
    2. PerkinElmer LS-50B
    3. Spectrofluorimeter
    4. Optimised geometry
  • AN.007.S20

    Dissociation kinetics of calcium-calmodulin and calcium-calmodulin-peptide complex using the SFA-20/SPEX stopped-flow fluorescence accessory

    1. Calmodulin
    2. target peptides
    3. stopped-flow accessory
    4. SPEX FluoroMax
    5. spectrofluorimeter
    1. ¹S. R Martin, J. F. Maune, K. Beckingham and P. M Bayley (1992) Eur. J. Biochem. 205:1107-1114
    2. ²W. A. Findlay, S. R. Martin, K. Beckingham and P. M. Bayley, Biochemistry, (1995), 34:2087-2094.
  • AN.008.S20

    Stopped-flow kinetics of Ellman's reagent with thioglycerol using the SFA-20/Beckman stopped-flow accessory optimised for use with the Beckman DU 7500 Diode array spectrophotometer

    1. stopped-flow accessory
    2. Beckman DU 7500
    3. diode array
    4. multi-variate global analysis
    1. ¹Carlton Paul, Kasper Kirschner and Gernot Haenish, Analytical Biochemistry, 101, 442-448 (1980)
  • AN.011.S20

    Rapid kinetics study of the displacement of calcium ions bound to FURA-2 using the SFA-20 stopped-flow accessory with a PTI spectrofluorimeter

    1. SFA-20 Stopped-flow accessory
    2. PTI QuantaMaster C-60
    3. Intracellular calcium ion
    4. Fura-2
    1. ¹Jackson, A.P., Timmerman, M.P., Bagshaw, C.R. and Ashley, C.C. (1987 FEBS Letters 216, 35-39
    2. ²G. Grynkiewicz, M. Peonie, and R.Y. Tsien, Journal of Biological Chemistry, 260, (1985), No. 6
  • AN.014.S20

    Measurement of the Reduction of Potassium Ferricyanide by L-Ascorbic Acid with a Shimadzu UV-1700 Spectrophotometer using the SFA-20 Stopped-Flow Accessory

    1. stopped-flow Accessory
    2. Shimadzu UV-1700
    3. Rapid kinetics
  • AN.015.S20

    Measuring the formation of 2,4-Dinitrophenol from 2,4-Dinitrophenol Acetate and Sodium Hydroxide using a Varian Cary 50 Spectrophotometer with the SFA-20/Varian Stopped-Flow Accessory

    1. stopped-flow Accessory
    2. Varian Cary 50
    3. Rapid kinetics
    4. SFA-20
  • AN.017.S20

    Measure the displacement of a Mant Nucleotide from a complex with S1 using a Varian Eclipse Fluorimeter with the SFA-20/Varian Stopped-Flow accessory

    1. Stopped-Flow Accessory
    2. Varian Eclipse
    3. Rapid Kinetics
    4. SFA-20
    5. Fluorescence
  • AN.018.S20

    Fluorescent measurements using the SFA-20 Stopped-Flow accessory with an ISS PC1 Fluorimeter

    1. Stopped-Flow Accessory
    2. SFA-20
    3. ISS PC1
    4. Rapid Kinetics
    5. Tryptophan
    6. Tyrosine
    7. Fluorescence
    8. Dead Time
    9. Calmodulin
  • AN.022.S20

    Stopped-Flow measurements using a rapid scanning, miniature fibre connected spectrometer

    1. Stopped-Flow
    2. SFA-20
    3. Ocean Optics
    4. CCD
    5. Rapid Scanning
    6. Kinetic Studio