DEVELOPMENT AND OPTIMIZATION OF A SPECTROPHOTOMETRIC METHOD WITH CLOUD POINT EXTRACTION FOR DETERMINATION OF GADOLINIUM

This work describes a simple, sensible, and low-cost analytical method, based on cloud-point extraction (CPE) of the surfactant (1,1,3,3-Tetramethylbutyl)phenyl-polyethylene glycol (Triton X-114), for the efficient extraction and sensible determination of gadolinium after its complexation with 1-(2-pyridylazo)-2-naphthol (PAN) and subsequent determination by ultraviolet-visible molecular absorption spectrophotometry at the wavelength of 556 nm. Full two-level and Doehlert experimental designs were applied to investigate and optimize the variables (pH, complexing concentration, and TX-114 concentration) involved in the extraction efficiency of Gd3+. The CPE was satisfactory for the determination of gadolinium with limits of detection (LoD) and quantification (LoQ) of 1.0 and 3.2 mu g L-1, respectively, as well as an enrichment factor of 9.4. Accuracy was confirmed by spike tests with recovery values between 98.4 and 78.3%. The precision was expressed as relative standard deviation (%RSD, n =3), being found: 2.3% (10 mu g L-1) and 2.7% (100 mu g L-1). The proposed analytical method is suitable for the determination of Gd in tap water and contrast agent solutions.

Automated summary

This work presents a simple, practical, and cost-effective analytical method for the extraction and determination of gadolinium using cloud-point extraction (CPE). The method achieves high efficiency and accuracy through experimental design and optimization of variables. It is suitable for the determination of gadolinium in tap water and contrast agent solutions.