CE-C4D for the Determination of Cations in Parenteral Nutrition Solution

© 2015 by Nova Science Publishers, Inc. All rights reserved. The capillary electrophoretic (CE) analysis of inorganic ions in parenteral nutrition solution in association with capacitively coupled contactless conductivity detection (C4D) is a simple, flexible, economic and eco-friendly method. The aim of this study was to improve the repeatability and linearity properties as well as the application of this validated method to estimate the quantity of each inorganic cation in commercial samples. The method is carried out on an uncoated fused silica capillary with 50 μm i.d. and 365 μm o.d. and 60 cm length of which 50 cm is the effective length. Before the actual analysis, the capillary is rinsed sequentially with 0.05 M H3PO4 for 10 minutes followed by water for 20 minutes. To ensure a stable baseline, an additional rinsing of the capillary by 0.1 M NaOH, water and background electrolyte (BGE) consisting of 8 mM of L-arginine and 5 mM of DL-malic acid has been performed. Both constant current (CC) and constant voltage (CV) CE separation show acceptable linearity (R2 < 0.995) for all cations in concentration ranges up to 100 μg/mL. The CC separation mode gives lower migration time (MT), better resolution and peak integration than the CV mode. Repeatability of peak area for individual cations is increased further by employing the rinsing sequence in-between sample injections as well as by using lithium chloride (LiCl) as internal standard. Although the CC mode is found to improve repeatability of peak area, it exhibits more day-to-day variability. The %RSD of the MT and the relative peak area (RPA) of sodium and potassium are however always within the specified limit. The CV mode shows good repeatability for calcium and magnesium. The sample quantification by calibration curve shows out-of-the-limit values for all analytes due to marked matrix interference. The standard addition method, in the same way proved ineffective to approximate the actual quantity of analytes in parenteral nutrition (PN) solutions. Finally, a single point calibration technique proved fruitful in the assay of cations by the use of simulated standard solution.edition: 1ststatus: publishe