Influence of Pectin as a green polymer electrolyte on the transport properties of Chitosan-Pectin membranes.

Novel blend membranes have been prepared from Chitosan (CH), Pectin (PEC) and their mixtures. The obtained samples were cross-linked and sulfonated before characterization. The results show that CH/PEC membranes display structural changes on the chemical and physical properties as a function of composition. DSC analysis reveals an endothermic peak due to the scission of the ionic pairs between carboxylic groups and ammonium groups, which produces a strong change on physical properties such as methanol permeability and proton conductivity. The methanol permeability decreases with the amount of Pectin from (4.24±0.04)×10-6cm2/s for pure Chitosan membrane to (1.51±0.03)×10-6cm2/s for blend CH/PEC membranes when the amount of Pectin is 50% (v/v). The proton conductivities of the blend membranes follow a similar behavior. For a pure CH membrane the conductivity is 2.44×10-3S/cm, decreasing with pectin content until the composition 50/50 (v/v), in which the conductivity drops almost one order of magnitude.

On-line preconcentration/determination of copper in parenteral solutions using activated carbon by inductively coupled plasma optical emission spectrometry.

A method for the on-line preconcentration of copper using a minicolumn packed with activated carbon and its subsequent determination by inductively coupled plasma optical emission spectrometry (ICP-OES) coupled with flow injection (FI) was studied. In order to determinate the copper concentration present in parenteral solutions; it was retained on activated carbon (AC) at pH 9.5. A sensitivity enrichment factor of 30-fold was obtained with respect to the copper determination by ICP-OES without preconcentration. The detection limit for the preconcentration of 25 ml of sample was 0.1 microgl(-1). The precision for the ten replicate determinations at the 2.5 microgl(-1) Cu level was 3.0% relative standard deviation (R.S.D.), calculated with the peak heights. The calibration graph using the preconcentration method for cooper species was linear with a correlation coefficient of 0.9996 at levels near the detection limits up to at least 200 microgl(-1). The method was successfully applied to the determination of copper in parenteral solutions.