Flow Fix, 1% Paraformaldehyde Fixative Kit is a sodium azide-free fixation buffer system for flow cytometry and immunofluorescence workflows. The final working solution is a neutral pH-buffered saline containing 1% w/v paraformaldehyde, prepared in 0.1 M phosphate buffer.
This kit is designed for fixation of hematopoietic cells and other compatible cell samples where preservation of light-scattering characteristics and fluorescence intensity is needed for subsequent flow cytometric analysis. The sodium azide-free formula is useful when azide should be avoided in fixation buffers, particularly in workflows where sodium azide could interfere with metabolic activity before fixation.
Once mixed and aliquoted, Flow Fix may be frozen for long-term storage. Thawed aliquots may be stored at 4°C for up to two weeks, and frozen aliquots may be stored for up to 5 years. Aliquoted solution may also be sterilized by autoclaving for room-temperature storage when prepared according to the technical data sheet.
Key Properties
- Sodium azide-free paraformaldehyde fixation buffer kit
- Final working solution contains 1% w/v paraformaldehyde
- Final buffer concentration: 0.1 M phosphate buffer
- Product Number: 25037
- Kit size: 1 kit
- Designed for flow cytometry and immunofluorescence workflows
- Supports fixation of hematopoietic cells for subsequent analysis
- Prepared from separate fixative and phosphate buffer components
- Storage: 4°C
Applications
Flow Cytometry Fixation
Used to fix cells for flow cytometric analysis while helping preserve light-scattering characteristics and fluorescence intensity.
Immunofluorescence Workflows
Suitable for fixation steps in immunofluorescent staining workflows where paraformaldehyde fixation is required before subsequent analysis.
Hematopoietic Cell Preparation
Designed for fixation of human and rodent lymphoid or hematopoietic cells in compatible sample preparation workflows.
Intracellular Cytokine Staining
May be used to fix cells for subsequent immunofluorescent staining of intracellular cytokines when validated for the target antibody and antigen system.
Sample Stabilization Before Analysis
Useful when fixed cell samples need to be stabilized for later flow cytometry or fluorescence microscopy analysis under controlled storage conditions.
Compatibility & Method Considerations
-
Fixative type: 1% paraformaldehyde in phosphate buffer
-
Formula: Sodium azide-free fixation buffer
-
Primary method: Flow cytometry and immunofluorescence sample preparation
-
Target samples: Compatible cell suspensions, including hematopoietic and lymphoid cell preparations
-
Method factors: Fixation performance depends on cell type, antibody system, antigen sensitivity, buffer composition, fixation time, temperature, and downstream staining conditions
For antigen-specific workflows, confirm that the antibody can detect its target after fixation. Fixation conditions may require optimization for different cell types, antigens, and staining panels.
Preparation Tips
- Combine the supplied fixative solution and phosphate buffer according to the technical data sheet to prepare the final 1% Flow Fix working solution.
- Filter the phosphate buffer into the same container as the fixative solution when preparing the final working solution.
- Use cold buffers and controlled incubation conditions when required by the validated staining or fixation protocol.
- For cell fixation, follow the recommended protocol for cell concentration, wash steps, fixation volume, incubation time, and temperature.
- Protect fluorescently stained samples from light before and after fixation.
- Document cell type, antibody panel, fixation time, buffer system, temperature, storage conditions, and analysis timing for reproducible results.
Handling & Storage
- Store kit components at 4°C.
- Protect from prolonged exposure to light.
- Keep containers tightly closed when not in use.
- Once mixed and aliquoted, freeze aliquots for long-term storage when appropriate.
- Thawed aliquots may be stored at 4°C for up to two weeks.
- Frozen aliquots may be stored for up to 5 years.
- Use standard laboratory handling practices.
Why Choose Polysciences?
Trusted by 6,000+ Researchers Worldwide
Cited in Thousands of Peer-Reviewed Studies
U.S. Manufacturing & Global Distribution
Reliable Delivery to 40+ Countries
Frequently Asked Questions
1. What is Flow Fix, 1% Paraformaldehyde Fixative Kit used for?
Flow Fix is used for cell fixation in flow cytometry, immunofluorescence, intracellular cytokine staining, and related sample preparation workflows.
2. What is the final paraformaldehyde concentration?
The final working solution contains 1% w/v paraformaldehyde in 0.1 M phosphate buffer.
3. Is Flow Fix sodium azide-free?
Yes. Flow Fix is a sodium azide-free fixation buffer system. Sodium azide should not be added when it may interfere with the intended cell workflow before fixation.
4. Can Flow Fix be used with fluorescently stained cells?
Yes. Flow Fix may be used to fix immunofluorescently stained cells to help preserve light-scattering signals and fluorescence intensities for later analysis. Protect samples from light and validate fixation conditions for the antibody panel.
5. How should Flow Fix be stored?
Store the kit at 4°C and protect it from prolonged exposure to light. Once mixed and aliquoted, frozen aliquots may be stored for long-term use, and thawed aliquots may be kept at 4°C for up to two weeks.
6. Can fixed cells remain viable?
No. Paraformaldehyde fixation preserves cell structure and staining signals for analysis, but fixed cells should not be considered viable for functional assays.
Safety & Documentation
Handle using standard laboratory practices and appropriate PPE. Refer to the Safety Data Sheet (SDS), Technical Data Sheet, and Certificate of Analysis for handling, storage, safety, preparation, and lot-specific guidance.
