Spectrophotometric and Voltammetric Studies on the Interaction of Heparin with Crystal Violet and its Analytical Application

Abstract

The interactions of heparin with crystal violet were studied by absorption spectrophotometry and  voltammetry in pH 3.0 Britton-Robinson (B-R) buffer solution. Heparin, which is negatively charged, can easily bind to the positively charged crystal violet to forma supramolecular ion-association complex. Owing to the formation of the new complex, the maximum absorption wavelength of crystal violet at 592nmdecreased and two new absorption peaks appeared at 510nmand 363nmafter the addition of  heparin. The oxidation peak current of crystal violet on glassy carbon electrode (GCE) at +0.84V(vs. SCE) also changed correspondingly without change of the peak potential, which also indicated that the binding reaction had taken place. Under the selected conditions a new spectrophotometric analytical method was established for heparin with the linear range between 0.10–4.0 mg L^–1) with a linear regression equation as ΔA = –0.002 + 0.227C (mg L^–1), (n = 8, γ = 0.997). The relative standard deviation for eleven parallel determinations of 0.40mgL^–1) heparin was 1.69% and the detection limit (3σ) was 0.09mgL^–1). Thisnew method was further applied to the determination of heparin sodium injection samples with satisfactory results.

KEYWORDS: Heparin, crystal violet, spectrophotometry, voltammetry, ion-association complex.