Determination of selenium in nuts by cathodic stripping potentiometry (CSP)

Area of Science:

• Analytical Chemistry
• Food Science
• Environmental Science

Background:

• Selenium is an essential trace element crucial for human health.
• Accurate determination of selenium content in food, particularly nuts, is important for dietary assessment.
• Existing methods for selenium analysis can be complex or have limitations.

Purpose of the Study:

• To develop and validate a novel method for quantifying selenium in nut samples.
• To assess the selenium content in various Sicilian nut varieties.
• To compare the proposed method with a standard analytical technique.

Main Methods:

• Nut samples were digested using nitric acid and dissolved in hydrochloric acid.
• Selenium determination was performed using cathodic stripping potentiometry in a specialized electrolyte solution (2 M CaCl(2) and 4 M HCl) to minimize oxygen interference.
• Analysis involved electrolysis at -150 mV for 60 s with a constant current of -30 microA.

Main Results:

• The proposed method achieved detection limits below 1.0 ng/g for selenium in nuts.
• Excellent precision was observed, with relative standard deviations ranging from 0.44% to 0.88%.
• Recovery rates were high, between 90.2% and 95.3%, indicating accuracy.
• Results correlated well (within 5%) with hydride vapor generation atomic absorption spectroscopy.
• Mean selenium concentrations in Sicilian almonds, hazelnuts, and pistachios were 531 ± 1, 865 ± 1, and 893 ± 4 microg/kg, respectively.

Conclusions:

• Cathodic stripping potentiometry provides a sensitive, accurate, and reliable method for selenium determination in nut matrices.
• The method is suitable for routine analysis and offers advantages in terms of simplicity and detection limits.
• The study quantified significant levels of selenium in Sicilian almonds, hazelnuts, and pistachios, contributing to nutritional data.