In this paper, a novel zirconium nanoparticles (Zr-NPs)-based solid-phase extraction (SPE) strategy was established for the accurate and sensitive determination of cadmium at trace levels prior to slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS) system. Zr-NPs were synthesised with a simple and fast method and utilised as adsorbents for the extraction of the analyte from aqueous samples. The primary factors affecting the extraction recovery such as nanoparticle amount, mixing type and period, type and volume of eluent were optimised by single variant experiments to obtain optimal extraction conditions. Under the optimised conditions, the calibration plot of the method showed a linear range of 2.0–25 µg L⁻¹ with a regression coefficient of 0.9993. The limit of detection and limit of quantification obtained were 0.44 and 1.46 µg L⁻¹, respectively. In order to make sure whether the developed method is applicable to complex matrices, an extraction procedure was successfully applied to wastewater samples. For this purpose, spiked recovery studies were performed at three different cadmium concentration. The per cent recoveries were obtained between 96.1% and 100.7% with low per cent relative standard deviations. Thus, the proposed method was validated and confirmed its high accuracy and precision with satisfactory recoveries.

In this work, a novel, efficient, simple and green solid phase extraction (SPE) method based on a pipette tip filled with zirconium nanoparticles (Zr-NPs) was developed for the sensitive determination of cobalt in soil samples via slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS). Zirconium nanoparticles providing repeatable and reproducible signals of the analyte were synthesized via a practical method and used as adsorbents. Extraction and preconcentration steps were performed in a customized pipette tip loaded with zirconium nanoparticles. All parameters having significant effects on the analyte signal (pH and volume of the buffer, amount of nanoparticles, type, concentration and volume of the eluent, sample volume and sample flow rate) and instrumental conditions were optimized to obtain the best experimental outcomes. Under the optimum conditions, the linear range of the developed method was found to be between 7.5 and 75 μg L⁻¹ with a correlation coefficient of 0.9998. The SPE method offered 56-fold enhancement in the detection power of FAAS with the limits of detection and quantification (LOD/LOQ) calculated as 2.2 and 7.2 μg L⁻¹, respectively. The developed method was applied to soil samples in order to test both its applicability and accuracy for real samples. The percent recoveries obtained were in the range of 90–101%, indicating the method's accuracy and applicability for complex matrices such as soil samples.

Different isotope dilution strategies were evaluated to quantify bisphenol A. High accuracy and precision were achieved by SS-LPME and ID ⁴ combination.