A dispersive liquid–liquid microextraction based on solidification of floating organic drop and spectrophotometric determination of uranium in breast milk after optimization using Box-Behnken design

• Published in: Microchemical journal 2017-09, Vol.134, p.327-332
• Main Authors: Souza, Anderson Santos, Siqueira, Rafael Pena, Prates, Romário Farias, Bezerra, Vanessa Moraes, Rocha, Daniela da Silva, Oliveira, Márcio Vasconcelos, Santos, Djanilson Barbosa
• Format: Article
• Language: English
• Subjects: Box-Behnken design; Breast milk; Caetité; DLLME-SFO; Uranium
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2017.06.024

A new procedure developed based on a preconcentration system using a dispersive liquid-liquid microextraction technique based on solidification of floating organic drop (DLLME-SFO) was combined with the molecular absorption spectrometry to determine uranium using 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP) as the complexing reagent. The optimization step was performed using two-level factorial design and the Box-Behnken design. The parameters analyzed were pH, Br-PADAP volume, extractant solvent volume and disperser solvent volume. The method allowed determining uranium with a limit of detection of 0.46μgL−1, limit of quantification 1.53μgL−1. The enrichment factor was estimated to be 76-fold. The precision expressed as relative standard deviation (RSD) for uranium concentrations of 2 and 10μgL−1 was 4.91% and 1.85% (n=15), respectively. Accuracy was assessed using recovery values ranging from 95.28% to 103.86%, which proves that this method does not suffer from a matrix effect and can be satisfactorily applied. The proposed method was applied to determine uranium in human milk samples. Fifteen samples were analyzed, and the uranium concentration ranged from 45.87±3.62μgL−1 to 160.97±7.00μgL−1. •Spectrophotometric trace determination of uranion•Uranium determination in breast milk lactating women from Caetité, Brazil•Improve of DLLME using solidification of floating organic drop technique•Women lived in the proximity of a uranium mine have uranium in breast milk.