Which LED wavelength and emission filter are best for EtBr stained gels?

EtBr (Ethidium Bromide) has an excitation peak around 302 nm (UV) and a secondary peak near 470 nm. A 470 nm blue LED transilluminator with a 590 nm long-pass emission filter is highly effective and eliminates UV hazards. A 525 nm long-pass filter can also be used if some background is acceptable.

What LED and filter combination is recommended for SYBR Green I?

SYBR Green I has excitation at approximately 494 nm and emission at 521 nm. A 470 nm blue LED transilluminator paired with a 510–540 nm band-pass or 505 nm long-pass emission filter provides excellent results. A 505 nm LED transilluminator can also be used for even better excitation efficiency.

What filter should I use for SYBR Gold?

SYBR Gold is excited effectively by both 302 nm UV and 470–505 nm blue LEDs. It emits around 537 nm. Use a 505 nm long-pass or 510–560 nm band-pass emission filter. A 470 nm LED transilluminator gives strong sensitivity for SYBR Gold without UV exposure.

Which emission filter works for GFP imaging in gel documentation?

GFP has excitation near 488–494 nm and emission near 507–510 nm. Use a 470 nm LED transilluminator with a 510 nm long-pass or 505/15 band-pass emission filter to block the LED light and capture GFP fluorescence. A 505 nm LED is also suitable.

Can I use the same emission filter for multiple fluorescent reagents?

A single 590 nm long-pass filter works well for EtBr, GelRed, and similar red-emitting dyes. For green-emitting reagents like SYBR Green, SYBR Gold, and GFP, a 510–540 nm band-pass or 505 nm long-pass filter covers all three. Having two filters — one for red and one for green emission — covers most common gel imaging reagents.

Gel Documentation System

縲縲Filter Guide for Various Fluorescent Reagent (Ex/Em)

Fluorescence Reagent Filter Guide (Ex / Em)

This page provides a practical reference for selecting suitable LED wavelengths and emission filters based on excitation (Ex) and emission (Em) spectra of commonly used fluorescent reagents in gel imaging and fluorescence observation.

EXCITATION (EX) EMISSION (EM) LED WAVELENGTH EMISSION FILTER DICHROIC FILTER

Selection Principle:Choose an LED wavelength that efficiently excites the fluorophore, and combine it with an emission filter that blocks excitation leakage while transmitting fluorescence emission. When excitation and emission spectra are close or overlapping, additional filtering such as a dichroic filter may be required to reduce background glow.

Quick Reference Table

Each row lists a reagent with its peak excitation (EX) and emission (EM) wavelengths. Click any row to jump to the detailed LED wavelength and filter combination for that reagent.

Reagent	EX nm	EX (Sub)	EM nm
Alexa Fluor 532	532		554
Cy3	550		570
DsRed	557		579
EtBr	300	518	605
FITC	490		525
Flamingo	512	271	535
Gel Green	250	500	530
Gel Red	270	510	600
GFP	488		507
mCherry	580		610

Reagent	EX nm	EX (Sub)	EM nm
mCitrine	516		529
Midori Green	490	290	530
SYBR Gold	495		540
SYBR Green I	498		522
SYPRO Orange	470		570
SYPRO Red	550	300	630
SYPRO Ruby	280	450	620
TagRFP	555		583
tdTomato	554		581
YFP	513		527

* Additional Ex/Em Reagent List Reagent List

Notice: This guide is intended for reference purposes only. It does not guarantee visibility of any specific fluorescence signal. Actual results may vary depending on LED intensity, filter quality, optical configuration and camera specifications.

Symbol Meaning

◎ Most suitable
◎* Most suitable
but an additional long-pass or dichroic filter may be required to reduce background.
○ Suitable
△ Usable, but with limited effectiveness compared with ◎ and ○.
× Not recommended

Alexa Fluor 532 fluorescence excitation and emission spectrum chart

Hover over the image to view LED and filter wavelengths

For cellular labeling in fluorescence microscopy and in cell biology.
Retains sulfonic acid which is
directly connected to the fluorescent. Especially bright with rhodamine derivative. The reagent with great
light stability

Thermo Fisher