Analysis of polyethylenimine by spectrophotometry of its copper chelate

Abstract

spopsisPolyethylenimine (PEI) forms a copper chelate with a N/Cu ratio of about 5 and with extinction coefficients of about 175 at 63$0 A. and 4250 a t 2694 A. Solutions of PEI-copper chelate obey Lambert's and Beer's Iaws and show increased optical density in the presence of chloride ion. Above pH 4.25, hydrogen ion has little effect. A comparison with the copper chelate of polyvmylamine suggests that PEI has a highly, branched structure. Analysis of PEI via its copper chelate is described. 1993 1994 V r .

Polyethyleneimine functionalized mesoporous diatomite particles for selective copper recovery from aqueous media

“…This number is, however, larger than the true ratio, as the films are highly cross-linked with non-nitrogen containing GA. The ratio is also 2-3 times larger than that reported at saturation for systems in solution [33,[43][44][45], and about 30% larger than reported for thin films of GA-crosslinked PEI in dilute copper solutions [33,43].…”

Biodegradable capsules as non-viral vectors for in vitro delivery of PEI/siRNA polyplexes for efficient gene silencing

“…An alternative method frequently used in literature is concentration determination via UV-Vis absorption spectroscopy. As PEI does not have a distinct intrinsic absorption peak, a characteristic peak can be generated by the formation of PEI-copper-complexes mediated by the amino groups of PEI [31]. However, this method bears some limitations; upon encapsulation of polyplexes, scattering and absorption of the capsule walls dominates, and thus makes an identification of the PEI-copper-complex absorption peaks complicated.…”

“…This ratio was found to be an optimal compromise between complexation of DNA/siRNA by PEI, fluorescence signal for tracking, and for the quantification of PEI. PEI quantification was achieved by using the ability of (primary) amino functionalities to form tetra-amino copper(II) complexes upon mixture with aqueous CuSO 4 solution [30,31] (cf. SI).…”

Copolymers of Ethylene Imine and N-(2-Hydroxyethyl)-ethylene Imine as Tools To Study Effects of Polymer Structure on Physicochemical and Biological Properties of DNA Complexes

“…Since condensation of DNA is known to be an important prerequisite for the formation of small polyplexes, the size range of the complexes made with the copolymers Perrine and Landis (1967). The titration analysis showed an increase of pKa value and buffer capacity with increasing ethylene imine content.…”