A novel direct spectrophotometric determination of traces of polyoxyethylene non-ionic surfactant in environmental water using meso-tetra (3,5-dibromo-4-hydrooxylphenyl) porphyrin–Pb (II) complex

Abstract

A novel direct spectrophotometric method is developed to determine traces of polyoxyethylene non-ionic surfactants (such as Triton X-100) in environmental water. It is based on the formation of a ternary complex, Meso-tetra (3,5-dibromo-4-hydrooxylphenyl) Porphyrin (T (DBHP) P)–Pb (II)–Triton X-100 in NaOH medium. Under the optimum reaction conditions, T (DBHP) P–Pb (II) complex reacts with Triton X-100 to form a yellow ternary complex immediately. The complex, which has a maximum absorption peak at 479 nm, is stable for at least 24 h. The mean molar absorption coefficient and the limit of detection for Triton X-100 is 1.1 × 10⁴ L mol⁻¹ cm⁻¹ and 0.02 µg mL⁻¹, respectively. Beer's law is obeyed in the concentration range of 0–0.5 mg mL⁻¹ Triton X-100. It is found that all the studied coexisting substances, especially cationic and anionic surfactants, which always seriously interfere in some reported methods, can be tolerated in considerable amounts. The method is used for the direct determination of PE in environmental water and has a good precision and accuracy.

Keywords:

• Polyoxyethylene
• Non-ionic surfactant
• Ternary complex
• Environmental water
• Spectrophotometry

Acknowledgements

The authors gratefully acknowledge the financial support from Southern Yangtze University.