Implementation of an ultrasonic assisted dispersive μ-solid phase extraction method for trace analysis of lead in aqueous and urine samples

Herein, an ultrasonic assisted dispersive micro-solid phase extraction (d-mu SPE) method along with a graphite furnace atomic absorption spectrometry (GF-AAS) for the measurement of lead at trace levels in water and urine samples was developed. In this regard, a silica-based amino-tagged nanosorbent (MCM-41@NH2) was successfully synthesized via a hydrothermal method. The surface properties of the synthesized nanosorbent was characterized by FT-IR, XRD, TEM, TGA and BET analytical techniques. Briefly, the nanosorbent was ultrasonically dispersed in the sample of interest for the adsorption of lead ions. Following the adsorption, the nanosorbent was removed off the sample and underwent the desorption process using a tiny volume of HCl, later on to be introduced to the GF-AAS for final lead determination. Meanwhile, to assess the efficiency of the adsorption and desorption processes, the influential variables such as pH, sorbent content, ionic strength and sonication time and desorption solvent features were all investigated and optimized in sequence. Subsequently, under the optimal conditions the calibration curve was found out to be linear over the concentration range of 0.1-1.0 mu g/L. In the meantime, the obtained assay accuracy in the analysis of real samples fell within the span of 92-110%, whilst the precision varied in the range of 4.8-9.2%. Finally, the applied method was successfully applied for the measurement of the trace levels of lead ions in various water and urine samples.