Which groups are on your target?
Consider NHS for primary amines and Maleimide for free thiols. For click chemistry, confirm the reaction partners first.
AF750 fluorescent dyes
Near-infrared emission, with 5 reactive dyes and 3 bioconjugates. Excitation near 750 nm and near-infrared collection; find labeling methods and documents for the target handle.
753nm
782nm
8
Optical values refer to AF750 NHS.
AF750 NHS spectral referenceNIR
AF750 product selection
Find AF750 dyes and conjugates by reactive group or recognition ligand.
Which recognition ligand do you need?
Compare Annexin V, WGA, CTB; check the sample and conditions.
| Product / catalog no. | Reactive form / ligand | Targets and applications | Documents |
|---|---|---|---|
| AF750 NHS EsterQH-10-1015 | NHS | Antibodies, proteins and other molecules with accessible primary amines | View product → |
| AF750 MaleimideQH-10-1015(Maleimide) | Maleimide | Targets with accessible free thiols | View product → |
| AF750 AzideQH-10-1015(Azide) | Azide | Targets with a compatible alkyne; confirm the click reaction system | View product → |
| AF750-PEG4-DBCOQH-10-1015(DBCO PEG4) | PEG4-DBCO | Azide coupling with a PEG4 spacer | View product → |
| AF750-PEG12-DBCOQH-10-1015(DBCO PEG12) | PEG12-DBCO | Azide coupling; evaluate a PEG12 spacer | View product → |
| AF750-Annexin VQH-10-1015(Annexin V) | Annexin V | Recognizes exposed PS; binding requires Ca²⁺ | View product → |
| AF750 WGAQH-10-1015(WGA) | WGA | Recognizes glycans containing GlcNAc or sialic acid | View product → |
| AF750 CTBQH-10-1015(CTB) | CTB | Recognizes GM1; consider binding and uptake conditions | View product → |
Showing 8 / 8 AF750 products
Spectra and detection conditions
AF750 NHS optical properties
- Reference product
- AF750 NHS · QH-10-1015
- Excitation peak
- 753 nm
- Emission peak
- 782 nm
- Molar extinction coefficient
- 290,000 M⁻¹ cm⁻¹
Values refer to this product’s specifications. Consult measurement records for solvent, pH and conjugation state.
Full product specifications →Excitation near 750 nm and near-infrared collection
Confirm excitation near 750 nm and collection around 780 nm. An IR-cut filter, detector response or other optics in a visible-light camera may limit signal. Increasing exposure does not replace checking the optical path.
A 780/40 bandpass nominally spans 760–800 nm and includes the 782 nm emission peak. Collected signal depends on the full emission spectrum, filter transmission and detector response; this is a passband example. Also check blocking of near-infrared excitation and detector response across the passband.
Read the detection guide →Multicolor combinations and controls
AF750 and AF790 can both contribute to a broad near-infrared window. Separate excitation does not exclude cross-excitation or collection overlap. Measure each single stain under every source and window to establish separation.
Multicolor detection considerations →Match the workflow to the target handle
Bioconjugates
For established recognition ligands, review the corresponding conjugates and their product-specific formulation, dose and storage conditions.
| Product | Recognition target and conditions |
|---|---|
| AF750-Annexin V | Phosphatidylserine; binding is Ca²⁺ dependent. |
| AF750 WGA | GlcNAc- or sialic-acid-containing glycans; consider sample preparation and intracellular signal. |
| AF750 CTB | GM1 ganglioside; confirm the application and treatment conditions. |
References
References on reaction chemistry, assay design and result interpretation.
Labeling a protein with fluorophores using NHS ester derivitization
Nanda JS, Lorsch JR. · Methods in Enzymology · 536:87–94 · 2014
Uses FAM ester labeling of a protein to explain primary-amine chemistry and labeling-efficiency assessment. It informs NHS workflow design; input and reaction conditions depend on the actual dye and sample.
Fluorescent-labeled antibodies: Balancing functionality and degree of labeling
Vira S, Mekhedov E, Humphrey G, Blank PS. · Analytical Biochemistry · 402(2):146–150 · 2010
Uses FITC-labeled anti-HA antibody to assess changes in labeling density and antigen binding. It informs input-series design and post-purification functional testing; DOL alone is insufficient for selecting a conjugate.
Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)
Cossarizza A, Chang HD, Radbruch A, et al. · European Journal of Immunology · 51(12):2708–3145 · 2021
Provides methodological guidance on detection settings, controls and experimental records for downstream conjugate evaluation.
Technical guides
AF750 · Labeling & detectionAF750 spectra and detection channelsAF750 NHS has 753/782 nm peaks. Check the excitation source, emission window and detector response separately.
Product peaks and excitation source
AF750 NHS has an excitation peak of 753 nm and an emission peak of 782 nm. Check the product name, source wavelength and collection window separately. Confirm excitation near 750 nm and collection around 780 nm. An IR-cut filter, detector response or other optics in a visible-light camera may limit signal. Increasing exposure does not replace checking the optical path.
Emission window and optical path
A 780/40 bandpass nominally spans 760–800 nm and includes the 782 nm emission peak. Collected signal depends on the full emission spectrum, filter transmission and detector response; this is a passband example. Also check blocking of near-infrared excitation and detector response across the passband.
Confirm settings with measured signals
The peak-position figure cannot compare brightness or calculate compensation. Use measured spectra to inspect filter coverage, then unstained and single-stain samples to assess background and signal. Keep gain or exposure fixed when comparing samples.
References
Chroma · Optical filters and bandwidth
chroma.com
Thermo Fisher · Sources and detection regions
tools.thermofisher.com
AF750 · Labeling & detectionNear-infrared detection with AF750 and AF790Neighboring dyes can enter the same detection window. Use single stains to check cross-excitation, spillover and separation.
Near-infrared detection with AF750 and AF790
AF750 and AF790 can both contribute to a broad near-infrared window. Separate excitation does not exclude cross-excitation or collection overlap. Measure each single stain under every source and window to establish separation.
Establish separation with controls
Measure each single-stain sample in every relevant channel and use an unstained sample for baseline fluorescence. Set conventional-flow compensation from these measurements or use dye- and treatment-matched references for spectral unmixing. If signals remain poorly resolved, change the dye panel or detection windows.
Comparison of products in similar regions
When comparing dye conjugates of the same target, match target concentration and labeling density and record each source and filter. A brighter reading in one channel may reflect better excitation or collection. Compare specific signal, background, recovery and function alongside raw intensity.
References
Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)
Cossarizza A, Chang HD, Radbruch A, et al. · European Journal of Immunology · 51(12):2708–3145 · 2021
Chroma · Optical filters and bandwidth
chroma.com
Labeling guide
Read guide →NHS and maleimide labeling routes
NHS labels primary amines; maleimide labels free thiols. Additives and reduction requirements determine sample preparation.
Labeling guide
Read guide →Azide and DBCO click-reaction pairing
Terminal alkynes pair with azides through CuAAC; DBCO pairs with azides through copper-free SPAAC.
Labeling guide
Read guide →Assessment of AF750-labeled conjugates
Compare labeling density, sample recovery, specific signal and background after purification, rather than total fluorescence alone.
Product-specific documents
Instructions, SDS, product specifications and CoA are catalog-specific. Request documents on the corresponding product page and include the vial lot number for a CoA.
AF750 NHS Ester
QH-10-1015
AF750 Maleimide
QH-10-1015(Maleimide)
AF750 Azide
QH-10-1015(Azide)
AF750-PEG4-DBCO
QH-10-1015(DBCO PEG4)
AF750-PEG12-DBCO
QH-10-1015(DBCO PEG12)
AF750-Annexin V
QH-10-1015(Annexin V)
AF750 WGA
QH-10-1015(WGA)
AF750 CTB
QH-10-1015(CTB)
Spectral and selection support
Include the target, reactive handles, buffer formulation, excitation source and emission window to help identify the product and supporting measurement information.
FAQ
How does the AF750 name relate to excitation and emission?
AF750 NHS has an excitation peak of 753 nm and an emission peak of 782 nm. Check the product name, source wavelength and collection window separately.
Does an 800 nm detection window establish AF750 compatibility?
The excitation source, lower passband edge and detector efficiency still matter. Some 800 nm windows may collect only part of this emission. Judge compatibility from actual filter curves and measurements.
Can AF750 be combined with neighboring dyes?
AF750 and AF790 can both contribute to a broad near-infrared window. Separate excitation does not exclude cross-excitation or collection overlap. Measure each single stain under every source and window to establish separation.
How do NHS, Maleimide, Azide and DBCO match targets?
Use NHS for primary amines, Maleimide for free thiols, Azide for terminal or strained alkynes, and PEG4-DBCO or PEG12-DBCO for azides. Each product page covers pretreatment, buffer and purification requirements.
Can reactive dyes and bioconjugates share storage conditions?
Follow each product page and vial label. Reactive dyes in this catalog are stored dry at −20°C and protected from light; aqueous conjugates have separate requirements. Prepared dye solutions and newly made conjugates cannot simply inherit dry-dye storage conditions.
Can molecular weight, CAS or extinction coefficients be borrowed from a similar dye?
Do not borrow these values. Reactive form, spacer, structure and salt form can affect them; confirm by catalog number. Request missing identity and calculation parameters through the product Documents tab rather than inferring them from a similar name.
How can I obtain instructions, measured spectra and a lot CoA?
Use Documents on the specific product page and describe the application and detection settings. Supply the catalog and vial lot numbers for a CoA. The displayed spectrum is a peak schematic and references concern methods; neither is a lot inspection result.