oa South African Journal of Chemistry - Spectrophotometric and voltammetric studies on the interaction of heparin with crystal violet and its analytical application
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 592 nm decreased and two new absorption peaks appeared at 510 nm and 363 nm after the addition of heparin. The oxidation peak current of crystal violet on glassy carbon electrode (GCE) at + 0.84V(ns. 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 ∆A = -0.002 + 0.227C (mg L-1), (n = 8, g = 0.997). The relative standard deviation for eleven parallel determinations of 0.40 mg L-1 heparin was 1.69% and the detection limit (3s) was 0.09 mg L-1. This new method was further applied to the determination of heparin sodium injection samples with satisfactory results.
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