. Author manuscript; available in PMC: 2011 Jan 28.

Published in final edited form as: J Phys Chem B. 2010 Jan 28;114(3):1336–1349. doi: 10.1021/jp906648q

Table 1.

Some Spectroscopic Characteristics of Molecular Probes.

Parameter	F18	QD585 (lot#45264A)	R18
	λ_max =498	-	λ_max =564
	λ_ex =488	λ_ex =488	λ_ex =488

Molar absorptivity ⁱ,
ε(M^-1cm^-1)@,λ_max	80,000^ia	-	95,400^ic
ε(M^-1cm^-1)@λ_ex	72,600	530,000	4,750

Quantum yield (ϕ_s) ⁱⁱ	0.88^iia	0.12^iic	0.3^iid

λ_{em max}. (nm)	520^iiia	585	585
Bandpass %T ⁱⁱⁱ	37	65	51

Overlap integral
J_D-R18 (cm³M^-1) ^iv	3.35×10^-13 ^iva	-	3.75×10^-13 ^iva
	1.96×10^-13 ^ivb		3.40×10^-13 ^ivb
	2.8×10^-13 ^ivc		3.09×10^-13 ^ivc

R₀-R18 (Å) ^v	61.0^va		52.2^va, 51.5±1^v′
	56.3^vb		51.3^vb
	57.3^vc		48.0^vc

Notes.

ⁱ

Extinction coefficients obtained from www.probes.invitrogen.com. (a) The extinction coefficients of fluorescein and derivatives vary from 85,000 for the NIST fluorescein solution standard reference material SRM 1932 to 75,000 for some FITC derivatives, and values are pH dependent. We have selected a median number here. (b) ibid. (c) Taken from ref (Cerione, R. A., McCarty, R. E., and Hammes, G. G. (1983) Biochemistry 22,769–776).

ⁱⁱ

Relative quantum yields, $φ_{s} = φ_{ref} \frac{I_{s}}{I_{ref}} \frac{O D_{ref}}{O D_{s}} \frac{n_{s}^{2}}{n_{ref}^{2}}$ , were calculated using the integrated intensity of sample relative to fluorescein, φ_ref = 0.93; or rhodamine B (0.31 in water (Magde et. al., Photochem. Photobiol. 1999) I_s and I_ref are the integrated band intensities. The optical densities (OD) of the sample (s) and reference (ref) were kept close. n is the index of refraction of the solvent; 1.32 for water. The experiments were perfomed in: (a) ethanol/PBS, (b) water (c) water, ϕ_s is accurate for the given lot number and excitation wavelength (see text and Wu et al Anal. Biochem. 2007, 364, 193-203 for details). (d) vesicles.

ⁱⁱⁱ

Bandpass filters used in a standard model BD FACScan flow cytometer (c.f. Figure 2 and Figure 4 in ref (Wu et al Anal. Biochem. 2007, 364, 193-203).

^iv

Calculated using Eqn. 3.(a) Overlap with absorption spectrum of R18 in Triton X-100. (b) R18 Spectrum in water. (c) Spectrum of H-dimer.

(a-c) Calculated using J values derived from iv. v′ Taken from Edinger, M.D., Domingue, R.P., Fayer, M.D. J. Chem. Phys. 1984, 80, 1246-1253.