Preconcentration of phosphate ions on graphene oxide decorated with lanthanum oxide from waters followed by energy dispersive X-ray fluorescence spectrometric determination

Katarzyna Pytlakowska; Karina Kocot; Barbara Hachuła; Ewa Talik

doi:10.1016/j.talanta.2023.124997

Preconcentration of phosphate ions on graphene oxide decorated with lanthanum oxide from waters followed by energy dispersive X-ray fluorescence spectrometric determination

Talanta. 2024 Jan 1;266(Pt 1):124997. doi: 10.1016/j.talanta.2023.124997. Epub 2023 Jul 26.

Authors

Katarzyna Pytlakowska¹, Karina Kocot², Barbara Hachuła², Ewa Talik³

Affiliations

¹ Institute of Chemistry, University of Silesia, Szkolna 9, 40-006, Katowice, Poland. Electronic address: katarzyna.pytlakowska@us.edu.pl.
² Institute of Chemistry, University of Silesia, Szkolna 9, 40-006, Katowice, Poland.
³ Institute of Physics, University of Silesia, 75 Pułku Piechoty 1a, 41-500, Chorzów, Poland.

PMID: 37517343
DOI: 10.1016/j.talanta.2023.124997

Abstract

A method for energy dispersive X-ray fluorescence spectrometric (EDXRF) determination of phosphate ions via the PKα line in diverse types of water samples is described. The method is based on ultrasonically assisted dispersive micro-solid phase extraction (USA-DMSPE) using lanthanum oxide supported on graphene oxide (La₂O₃-GO) as a solid adsorbent. Under optimal preconcentration conditions, i.e. sample pH = 5, sample volume 50 mL, adsorbent dose 0.8 mg, sonication time 30 min, a linear response was obtained between the phosphate concentration and the measured analytical signal in the range of 2-300 ng mL^-1 with a correlation coefficient of 0.9995. The developed procedure is characterized by good detection and quantification limits of 0.4 and 1.32 ng mL^-1. The inter-day and infra-day precision of the method tested at analyte ion concentrations of 5, 50, and 200 ng mL^-1 ranges from 1.1 to 4.4% and 1.2-4.7%, respectively. The accuracy of the method was verified by the standard addition method and the inductively coupled plasma atomic emission spectrometry (ICP-OES) comparative technique. The method was implemented for the analysis of various water samples, including artificial seawater. The phosphate content in studied water samples ranges from 23.8 to 121 ng mL^-1. Recoveries in samples enriched with phosphates with a known concentration of 94-102%, as well as a relative difference of 1.5-3.8% between results obtained by USA-DMSPE/EDXRF and ICP-OES indicate the usefulness of the method for the quantitative determination of phosphate ions in natural waters. Moreover, the mechanism of chemisorption in the tested system was discussed and the maximum adsorption capacity of La₂O₃-GO towards phosphate ions (90.1 mg g^-1) was determined.

Keywords: Determination of phosphates in waters; EDXRF determination of phosphates; La(2)O(3)-GO for phosphates preconcentration; Ultrasonically assisted dispersive micro-solid phase extraction (USA-DMSPE).