Montmorillonite grafted on a cellulosic paper as a novel layered sorbent for microextraction by packed sorbent in combination with HPLC for determination of carvedilol in biological samples

Abstract

In the present research, a novel nano-structured sorbent based on grafted montmorillonite on a cellulosic paper (MMT/Cell) has been prepared by chemically bonding to the surface of a cellulosic paper by glutaraldehyde as a cross linker. The prepared thin film was applied as the layered sorbent packed into a syringe for microextraction by packed sorbent (MEPS) of carvedilol (CAR) from biological samples followed by high performance liquid chromatography-ultra-violet absorption (HPLC-UV) detection. The morphology and the surface characteristics of the prepared thin layers were studied applying scanning electron microscopy (SEM) and their elemental analysis was studied by energy dispersive X-ray spectroscopy (EDX). Attenuated total reflection-Furier transform infrared spectroscopy (ATR-FTIR) was employed to study the presence of various functional groups on the MMT/Cell surface. The essential parameters affecting the extraction efficiency such as pH, sorbent layers, extraction draw-discard cycles, desorption draw-eject cycles, elution solvent and its volume were optimized. The linear dynamic range of the developed method was in the range of 1.5 to 300 ng mL−1 and the limit of detection (LOD) was 0.5 ng mL−1. The precision of the MEPS-HPLC-UV method in terms of relative standard deviation percentage (RSD %) considering three replications of extraction from spiked deionized water (100 ng mL−1) was 6.8%. Standard addition method was applied to determine CAR in urine and plasma samples, and the relative recovery percentage was 90.2 % and 80.0 % for urine and plasma samples, respectively, indicating the capability of the developed MEPS-HPLC-UV method to extract and determine CAR in biological samples.