Magnetic solid phase microextraction of cadmium in water and food samples on Escherichia coli immobilized to magnetic conductive carbon black (Vulcan XC-72) prior to its determination by flame atomic absorption spectrometry.

Abstract

Magnetic solid phase microextraction method (MSPME) is suggested due to simpler, faster, and utilizes less solvent than standard extraction methods. Non-active bacteria (Escherichia coli) were used as biosorbents and immobilized on support magnetic conductive carbon black (Vulcan XC-72) to preconcentrate cadmium. This new magnetic biosorbent composite was characterized using FTIR, SEM-EDX, and BET. Central composite design (CCD) and Plackett-Burman design (PBD) were applied to evaluate pH, biosorbent amount, sample volume, and vortex time relationships to achieve an optimum response. The matrix effects of certain cations and anions on analyte ions were examined. Limits of detection (LOD) and quantification (LOQ) were 0.6 and 2.0 μg L-1, respectively. Preconcentration factor (PF) and enhancement factor (EF) were 100 and 88, and the adsorbent capacity was 90.3 mg g-1. Intraday and interday RSD were 1.88 and 1.98 %. The calibration curve was linear from 2.0 to 40 μg L-1. Method accuracy was verified by analyzing certified reference materials. The optimized approach achieved high efficiency in recovering cadmium in water, food, and soft drink samples, showing an affordable and fast technique for analyzing food directly at the source, providing valuable support for safeguarding public health and monitoring environmental safety.