Resonance light scattering determination of metallothioneins using levofloxacin−palladium complex as a light scattering probe

A novel method of resonance light scattering (RLS) was developed for the analysis of trace metallothioneins (MTs) in human urine. In a CH3COOH–CH3COONa buffer solution of pH 4.5, the formation of a complex between levofloxacin (LEV)–Pd and MTs led to enhance the RLS intensity of the system, and the enhanced RLS intensity at 468 nm was proportional to the concentration of MTs in the range of 0.059–22.4 μg mL−1. The linear regression equation was ΔI = 127.5 ρ (μg mL−1)–88.02 with a correlation coefficient of 0.9992, and the detection limit of 17.8 ng mL−1. The relative standard deviation and the average recovery were 3.8–5.4% (n = 11) and 92.15%, respectively. The proposed method is convenient, reliable and sensitive, and has been used successfully for the determination of trace MTs in human urine samples.

[Pd(LEV)2]4+[Pd(LEV)2]4+ can interact with MTs to form an ion-association complex by electrostatic interaction at pH 4.5. Owing to the charges on the surface of MTs were neutralized by [Pd (LEV)2]4+, the bigger association particles were formed by hydrophobic interaction, resulting in increasing intensity of RLS.Figure optionsDownload as PowerPoint slideHighlights
► A novel method for the determination of MTs in human urine was developed.
► The proposed method was inexpensive and sensitive, and can be completed under ordinary temperature.
► The mechanism of interaction of MTs with LEV–Pd chelate was discussed.