Table 20.3 Molecular Probes pH indicator dextrans, in order of decreasing pKa.
|Dye||Cat #||pKa *||Measurement Wavelengths||Application Notes|
|SNARF||D3303, D3304||~7.5||Emission ratio 580/640 nm excited at 514 or 488 nm|
|BCECF||D1878, D1880||~7.0||Excitation ratio 490/440 nm detected at 530 nm|
|Fluorescein||D1821, D1823, D1844, D3305||~6.4||Excitation ratio 490/450 nm detected at 520 nm|
|Fluorescein and tetramethylrhodamine||D1951||~6.4||Excitation ratio 495/555 nm detected at 580 nm †|
|pHrodo||P10361||NA ‡||Emission at 585 nm when excited at 540–560 nm|
|Oregon Green 488||D7170, D7172||~4.7||Excitation ratio 490/440 nm detected at 520 nm|
|Oregon Green 514||D7176||~4.7||Excitation ratio 510/450 nm detected at 530 nm|
|LysoSensor Yellow/Blue||L22460||~4.2||Excitation ratio 340/400 nm detected at 520 nm; emission ratio 450/510 nm excited at 365 nm|
|* pKa values are those determined for the free dyes. Actual values for dextran conjugates may differ by up to +/– 0.3 pH units and may vary with production lots. † Ratiometric emission measurements at 520/580 nm (with excitation at 495 nm) are also possible in principle; however, the response may be complicated by fluorescence resonance energy transfer. ‡ NA = Not applicable. pHrodo pH indicator exhibits a complex pH titration profile. Decreasing pH (from pH 9 to pH 2) produces a continuous (but nonlinear) fluorescence increase.|
For Research Use Only. Not for use in diagnostic procedures.