Preconcentration and Speciation of Sb(III) and Sb(V) in Water Samples and Blood Serum after Cloud Point Extraction Using Chemometric Tools for Optimization

Abstract

A new Sb(III) and Sb(V) preconcentration and speciation method, optimized by multivariate design using cloud point extraction (CPE) with determination by graphite furnace atomic absorption spectrometry, is described. It is based on the formation of Sb(III) complexes with ammonium O, O- diethyl dithiophosphate (DDTP) in acid medium in the presence of Triton X-114. The Sb(V) is determined after quantitative reduction with L-cysteine, and its concentration is calculated by subtracting Sb(III) from the total antimony amount. The method provides a linear calibration range from 0.25 to 16.0 µg L⁻¹ (r > 0.994) and limits of detection and quantification of 0.08 µg L⁻¹ and 0.25 µg L⁻¹, respectively. A high preconcentration factor was found to be 229-fold by preconcentrating 12.0 mL of sample. The proposed method was successfully applied for the preconcentration and speciation of Sb(III) and Sb(V) in water samples and blood serum, where satisfactory recovery values were obtained, thus attesting to the feasibility of the method.

Keywords:

• Antimony
• atomic absorption
• cloud point extraction
• multivariate design
• speciation

The authors would like to thank the CNPq and FAPEMIG for financial support and fellowships. The authors also would like to thank Profa. Maria Antonieta Alvarenga for language assitance.

Notes

CC = chelating agent concentration (DDTP); SC = surfactant concentration (Triton X-114); BT = bath temperature; Salt = salt use [NaCl 1% (w/v)].

CC = chelating agent concentration (DDTP); SC = surfactant concentration (Triton X-114)

R ² = 0.90996 and R ² adjusted = 0.74789

Pt = pyrolysis time, PT = pyrolysis temperature, and AT = atomization temperature.

HG = hydride generation; ETV-ICP-AES = electrothermal vaporization inductively coupled plasma atomic emission spectrometry; SFI-HGAAS = segmented flow injection-hydride generation atomic absorption spectrometry (SFI-HGAAS); LD = limit of detection for Sb(III); PF = preconcentration factor; CI = consumptive index; NI = not informed; GF = AAS = graphite furnace atomic absorption spectrometry.

* Obtained by difference between Total Sb and Sb(III).

**The results are expressed as mean value ± SD based on three replicate (n = 3) determinations. Confidence interval, 95%.