Use of new polymeric composites for preconcentration of trace Ag⁺ ions from the selected mushroom/vegetables by ultrasound-assisted cloud-point extraction coupled to microvolume UV-Vis spectrophotometry

ABSTRACT

The magnetic nano-composites based on the tris(hydroxymethlmethyl)aminomethane-modified maleic anhydride-co-styrene copolymers and Fe₃O₄ nano-particles were prepared as new potential chelating agents for ultrasound-assisted-cloud point extraction (UA-CPE) and pre-concentration of trace levels of Ag⁺ ions from aqueous solutions. The structures of the nano-composites were characterised via FT-IR, ¹H-NMR and XRD analysis. After structural characterisation of composites, Ag⁺ ions were detected by micro-volume UV-vis spectrophotometry at 347 nm. The variables affecting complex formation and extraction efficiency for separation/pre-concentration of the Ag⁺ ions from various food matrices were evaluated and optimised in detail. Under the optimised conditions, the method shows a good sensitivity with linearity range from 10 to 350 µg L⁻¹ and 4 to 160 µg L⁻¹ for amidic and imidic composites, respectively, with a better correlation coefficient than 0.9825. The limits of detection, intra- and inter-day precision (as RSDs%) and recovery rates for six replicate determinations of Ag⁺ ions at levels of 25 and 100 μg L⁻¹ were 4.28/1.21 μg L⁻¹, 2.4–4.1% and 92–98% for the modified copolymers, respectively. The pre-concentration factor for Ag⁺ ion from pre-concentration of 35-mL sample was 70. A significant matrix effect was not observed for the triplicate measurements of 100 µg L⁻¹ Ag⁺ in the presence of various interfering species below their maximum concentrations allowed in this method, for Ag⁺ ions. The accuracy of the method was confirmed by analysis of the two certified samples. The method was successfully applied to determine low levels of Ag⁺ ions in mushroom and vegetable samples, and satisfactory recoveries were obtained in the range of 91-97% with lower RSD than 5.1% for the spiked samples.

KEYWORDS:

• Ultrasound-assisted-cloud point extraction
• tris modification
• copolymers
• micro-volume UV-vis spectrophotometry
• Ag⁺ ions
• vegetables/mushrooms

Acknowledgments

The financial support from the Scientific Research Projects of the Commission, CUBAP, University of Cumhuriyet (Sivas, Turkey), with code of F-604 is gratefully acknowledged. For the FT-IR, ¹H-NMR and XRD spectroscopic characterisation of the modified and magnetized copolymers with tris and Fe₃O₄, respectively, we would like to thank the technical staff of the Cumhuriyet University and the advanced technological research and application center (CUTAM) for the technical assistance and support. For allowing me to make use of all the facilities of the analytical research laboratory for conducting the present study, I would like to express my deepest gratitude to Prof. Dr. R. Gürkan. Also, thanks are due to him for his meaningful helps and valuable contributions in critical evaluation of the present article.

Compliance with ethics requirements

Author has no financial relationship with the organization that sponsored the research.

Disclosure statement

No potential conflict of interest was reported by the author.

Ethical approval

This article does not contain any studies with human or animal subjects.

Additional information

Funding

This work was supported by the The Scientific Research Projects of the Commission, CUBAP, University of Cumhuriyet [Grant number F-604 project number].