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Cal-520L™ maleimide

Chemical structure for Cal-520L™ maleimide.
Chemical structure for Cal-520L™ maleimide.
Ordering information
Price ()
Catalog Number20611
Unit Size
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Additional ordering information
InternationalSee distributors
ShippingStandard overnight for United States, inquire for international
Physical properties
Molecular weight991.78
Spectral properties
Excitation (nm)493
Emission (nm)515
Quantum yield0.751
Storage, safety and handling
H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22
StorageFreeze (< -15 °C); Minimize light exposure


Molecular weight
Excitation (nm)
Emission (nm)
Quantum yield
Calcium measurement is critical for numerous biological investigations. Fluorescent probes that show spectral responses upon binding calcium have enabled researchers to investigate changes in intracellular free calcium concentrations by using fluorescence microscopy, flow cytometry, fluorescence spectroscopy and fluorescence microplate readers. Cal-520L has been proven to be one of the best green fluorescent calcium indicators as a low affinity calcium indicator. Conceivably this thiol-reactive Cal-520L maleimide could be coupled to an IgG or other carrier molecules to prepare a calcium-sensitive bioconjugate for monitoring calcium change spatially for a specific target.


Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of Cal-520L™ maleimide to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM100.829 µL504.144 µL1.008 mL5.041 mL10.083 mL
5 mM20.166 µL100.829 µL201.658 µL1.008 mL2.017 mL
10 mM10.083 µL50.414 µL100.829 µL504.144 µL1.008 mL

Molarity calculator

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Spectral properties

Excitation (nm)493
Emission (nm)515
Quantum yield0.751


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