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Life Technologies Flow Cytometer Alignment & Linearity Beads

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Instrument performance, proper compensation, and accurate cell counting are critical to collecting and analyzing accurate experimental data.

Powered by Molecular Probes® dye technologies, our flow cytometer alignment & linearity beads, absolute cell counting beads, compensation tools, and cell sizing beads ensure that your flow cytometer and experimental design are tuned for maximal performance to provide accurate data collection and analysis.

  • Confidence—ensure the reliability of optimal daily instrument performance
  • Performance—uniform production creating ideal reference standards
  • Reliability—minimal variation for consistent data acquisition
  • Compatibility—full range of tools for any instrument

Beads for Laser Alignment AlignFlow™ and AlignFlow™ Plus flow cytometry alignment beads are reliable references for aligning, focusing, and calibrating flow cytometers. These fluorescently stained, polystyrene microspheres are highly uniform with respect to size and fluorescence intensity, resulting in low CVs. The beads approximate the size, emission wavelength, and intensity of many biological samples and permit the calibration of the flow cytometer’s laser source, optics, and stream flow without wasting valuable and sensitive experimental material (Figure 1).

Figure 1. AlignFlow™ flow cytometry alignment beads excited at 488 nm by an argon-ion laserand monitored in three emission channels. The broad fluorescence emission is detected in all three channels. Note the exceptionally small variation of fluorescence intensity of the beads. Contributed by Carleton Stewart, Roswell Park Cancer Institute.


DescriptionBead SizeExcitationEmissionCat. no.
AlignFlow™ Flow Cytometry Alignment Standards 2.5 µm UV, 405 400-470 A7304
488, 532 515-660 A7302
630-660 670-720 A14385
633 645-680 A7312
AlignFlow™ Plus Flow Cytometry Reference Standards 6.0 µm UV, 405 400-470 A7305
488, 532 515-660 A7303
630-660 670-720 A14836
633 645-680 A7313

Beads for PMT Linearity

LinearFlow™ flow cytometry linearity kits are designed to provide 6 precisely determined bead intensity levels to monitor the linearity of the instrument and its PMTs. As reference standards, these fluorescent linearity beads can be used to quantitate the relative fluorescence of labeled cells, to evaluate the fluorescence stability of a sample, and to monitor instrument performance and reproducibility. Colors are available for a multitude of excitation lines and emission channels to allow any PMT to be monitored regardless of instrument manufacturer.

  Figure 2. Fluorescence intensities of the six bead suspensions supplied in the LinearFlow™ Red Flow Cytometry Intensity Calibration Kit.


DescriptionBead SizeExcitationEmissionCat. no.
LinearFlow™ Flow Cytometry Intensity Calibration Kits 2.5 µm UV, 405 430 L14812
488 525 L14821
488, 532 575 L14814
488, 532 620 L14816
633 660 L14818
6.0 µm UV, 405 430 L14813
488 525 L14822
488, 532 575 L14815
488, 532 620 L14817
633 660 L14819

Beads for Cell Sorter Setup

Molecular Probes® PeakFlow™ flow cytometry reference beads are reliable standards for flow cytometry instrument setup and calibration. These fluorescently stained, polystyrene microspheres are highly uniform with respect to size and fluorescence intensity. The dyes used in the manufacture of PeakFlow™ beads have been carefully selected to provide emission peaks coincident with cells labeled with commonly used fluorescent dyes. The emission profiles for these standards are intentionally narrow in comparison to cells labeled with a corresponding fluorescent dye. Consequently, PeakFlow™ flow cytometry beads serve as reference sources with emissions centered on the expected fluorescence maxima of the experimental samples.

Figure 3. Normalized emission spectra of PeakFlow™ flow cytometry reference beads (solid line) and fluorescein-labeled cells(dashed line). The narrow emission spectrum of PeakFlow™ beads is approximately centered on the broader emission spectrum of fluorescein.

ProductColorLaserEx (nm)Em (nm)Fluorophore matchesSize (µm)Cat. No.
PeakFlow™ Flow Cytometry Reference Beads Blue UV, 405 400 460 DAPI, Hoechst dyes 2.5 P14825
6 P14826
Green 488 505 5155 FITC, Alexa Fluor® 488 2.5 P14827
6 P14828
Orange 488, 532 570 575 R-PE, Rhodamine, Alexa Fluor® 546 2.5 P14829
6 P14830
Carmine 488, 532 580 620 PI, Texas Red®, Alexa Fluor® 594 2.5 P14831
6 P14832
Claret 633 645 680 Cy®5 6 P24670
Ultrared 633 665 695 Cy®5.5 6 P24671
Infrared 633 735 770 Cy®7 6 P24672

Beads for Size Calibration

The Flow Cytometry Size Calibration Kit provides a set of microsphere suspensions to serve as reliable size references for cytometry users. The kit contains six suspensions of unstained polystyrene microspheres, each with a known diameter determined by transmission electron microscopy. The size of cells in an experimental sample can be estimated by comparing the FSC signals with those of the reference microspheres. The microspheres function as reproducible size markers and can be used intermixed with the experimental sample or in parallel runs.

Figure 4. Histogram analysis of the forward scatter intensity (FSC) log channel values of the six polystyrene microsphere samples supplied in our Flow Cytometry Size Calibration Kit. FSC measurements were performed on a Becton Dickinson FACScan® flow cytometer using excitation at 488 nm.