Internal Standardization in Dispersion Systems: an Efficient Application to Determine Mg in Crude Vegetable Oils by FS-FAAS
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This study established two sample preparation procedures based on dispersion systems for the determination of Mg in crude vegetable oil by IS-FS-FAAS. The emulsions were obtained with 0.10 g of samples [0.5% (m/v)] + 200 μL HNO3 [1.0% (v/v)] + 200 μL Triton X-100 [1.0% (v/v)] in 16 mL of anhydrous ethanol [80% (v/v)] and 3.50 mL of aqueous phase [17.5% (v/v)], whereas the microemulsions were obtained with 0.10 g of samples [0.5% (m/v)] + 200 μL HNO3 [1.0% (v/v)] + 200 μL Triton X-100 [1.0% (v/v)] in 18 mL of 1-butanol [90% (v/v)] and 1.50 mL of aqueous phase [7.5% (v/v)]. To overcome non-spectral interference, Cd, Co, and Cu were used as internal standards, and the slopes of calibration curves for Mg in 1.0% (v/v) HNO3 aqueous solution, anhydrous ethanol + 1.0% (v/v) Triton X-100, and 1-butanol + 1.0% (v/v) Triton X-100 showed no significant difference at the 95% confidence level using Co and Cu. Calibration curves were obtained by plotting AMg/ACo and AMg/ACu vs Mg concentration with linear correlation coefficients better than 0.9972 and 0.9986, respectively. The accuracy was evaluated using recovery tests, and recoveries of 98.4–106.6% (IS-Co) and 93.9–106.9% (IS-Cu) were obtained. The RSD (n = 5) were 0.4–3.6% (IS-Co) and 0.3–3.6% (IS-Cu), and LOD were 0.1 μg g−1 (IS-Co) and 0.2 μg g−1 (IS-Cu). The content of Mg in four crude vegetable oil varied in the range of 8.91 ± 0.30 to 163.88 ± 0.48 μg g−1 for both dispersion systems with RSD < 4.22%.
KeywordsMagnesium Alternative oilseed crop Internal standardization Emulsion Microemulsion
This work was supported by the Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul (Fundect, Process 23/200.665/2012) and FINanciadora de Estudos e Projetos (FINEP, contract: 04.13.0448.00).
Compliance with Ethical Standards
Conflict of Interest
Liriana M Roveda and Jorge Luiz Raposo Jr. declare that they have no conflict of interest.
This manuscript does not contain any studies with human participants performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.
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