ChemicalName: 5,10,15,20-Tetraphenyl-21H, 23H-porphinetetrasulfonic acid, disulfuric acid, tetrahydrate
CAS: 35218-75-8 (as an anhydride)
Appearance: Deep green or deep greenish blue powder
Molar absorptivity (pH 6.5): ≥510,000 (around 413 nm)
MW: 1203.21, C44H30N4O12S4, 2H2SO4, 4H2O
Storage Condition: ambient temperature, protect from metal and moisture
Shipping Condition: ambient temperature
TPPS is a water-soluble porphyrin that is reddish-purple in aqueous solution at pH 6.5 (maximum wavelength: 413 nm, molar absorptivity: 5.1x105) and green at pH 4 (maximum wavelength: 434 nm, molar absorptivity: 5.0x105). Its proton dissociation constants are reported to be pKa1=4.86 and pKa2=4.96. TPPS selectively forms a complex with Cu2+ in acidic conditions, and with Cd, Cu, Fe, Pb, and Pd in alkaline conditions.
1. A. D. Adler, et al., A Simplified Synthesis for Meso-tetraphenylporphin. J Org Chem. 1967;32:476-476.
2. J. Itoh, et al., Spectrophotometric Determinaton of Copper with α, β, γ, δ-Tetraphenylporphine Trisulfonate. Anal Chim Acta. 1975;74:53-60.
Table 1 Colorimetric Detection Conditions Using TPPS