Molecularly Imprinted Polymer as Sorbent Phase for Disposable Pipette Extraction: A Potential Approach for Creatinine Analysis in Human Urine Samples

Abstract

The traditional creatinine determination is made by a spectrophotometric method. However, some interferents present in biological samples can decrease the sensitivity in the determination of creatinine in urine samples with this spectrophotometric method. Due to this, this study developed a new molecularly imprinted polymer (MIP) as a sorbent phase to disposable pipette extraction (DPX) for the creatinine determination in urine samples by high-performance liquid chromatography with UV detection (HPLC/UV). The synthesized polymer showed a high superficial area presenting a first-order kinetic reaction and a high selectivity for creatinine compared to the non-molecularly imprinted polymer. The main DPX variables were evaluated: number of draw/eject cycles, pH solution, and type of the desorption solvent. The developed methodology showed an inter and intra-day precision of 1.3 to 2.0% and 0.8 to 1.6% respectively, the accuracy values ranging from 82.3% to 102.1% respectively, and recovery values between 96.5 to 101.3% with the limit of quantification of 0,339 g L-1. The developed methodology was applied to real urine samples which showed creatinine concentrations ranging from 0.55 to 6.61 g L-1. Thus, the developed DPX-MIP-HPLC/UV methodology showed to be efficient for creatinine determination, reducing the time of analysis (3 min), solvent uses, and increasing the selectivity.