. 2026 Feb 4;110(1):56. doi: 10.1007/s00253-026-13734-z

Table 1.

Characteristic and parameters of standards used in this study (Tsien 1998; Shaner et al. 2005)

Standard	Additional information and supplier	Excitation maxima (nm)	Emission maxima (nm)	Mass	Extinction coefficient ɛ (M⁻¹ cm⁻¹⁾	Purity %	Stock conc. and measured RFUs [-]
In-house EmGFP standard	Commercial plasmid In-house purification	487	509	26.9 kDa	57,500	78% (from SDS-PAGE)	12.6 ± 0.0 g/L from A₄₈₇ (n = 3), 49,043.8 ± 2009.7 for dilution 1:200, 63.0 mg/L
GFP standard	Commercial standard	395/475	509	26.9 kDa	25,000	> 70% (from SDS-PAGE)	1.0 g/L, 40,662.7 ± 894.3 for dilution 1:2, 500 mg/L
Sodium fluorescein (Na-F*)	IUPAC name: 3′,6′-dihydroxyspiro[isobenzofuran-1(3H),9′-[9H]xanthen]−3-one Commercial standard	485	514	332.31 g/mol	93,000	-	2 μM equivalent to 0.752 mg/L in 100 mM NaOH, 49,102.7 ± 666.9 for dilution 1:2, 0.376 mg/L in 100 mM NaOH

Standard

Additional information and supplier

Excitation maxima (nm)

Emission maxima (nm)

Mass

Extinction coefficient ɛ (M⁻¹ cm⁻¹⁾

Purity %

Stock conc. and measured RFUs [-]

In-house EmGFP standard

Commercial plasmid

In-house purification

487

509

26.9 kDa

57,500

78% (from SDS-PAGE)

12.6 ± 0.0 g/L from A₄₈₇ (n = 3), 49,043.8 ± 2009.7 for dilution 1:200, 63.0 mg/L

GFP standard

Commercial standard

395/475

509

26.9 kDa

25,000

> 70% (from SDS-PAGE)

1.0 g/L, 40,662.7 ± 894.3 for dilution 1:2, 500 mg/L

Sodium fluorescein (Na-F*)

IUPAC name: 3′,6′-dihydroxyspiro[isobenzofuran-1(3H),9′-[9H]xanthen]−3-one

Commercial standard

485

514

332.31 g/mol

93,000

2 μM equivalent to 0.752 mg/L in 100 mM NaOH, 49,102.7 ± 666.9 for dilution 1:2, 0.376 mg/L in 100 mM NaOH