Simultaneous determination of Cd and Fe in grain products using direct solid sampling and high-resolution continuum...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Food Science

Background:

• Cadmium (Cd) is a toxic element requiring routine monitoring in food.
• Iron (Fe) fortification in grain products is mandated by Brazilian law to combat anemia.
• Simultaneous determination of Cd and Fe in grains presents analytical challenges due to their antagonistic effects and differing properties.

Purpose of the Study:

• To develop a routine screening method for the quasi-simultaneous determination of cadmium and iron in grain products.
• To utilize high-resolution continuum source electrothermal atomic absorption spectrometry (HR-CS ETAAS) with direct solid sampling.
• To ensure accuracy and reliability for regulatory compliance and public health.

Main Methods:

• Employed direct solid sampling with HR-CS ETAAS.
• Utilized primary (228.802 nm) and secondary (228.726 nm) absorption lines for Cd and Fe, respectively.
• Investigated chemical modifiers, selecting a tungsten and iridium mixture for optimal stabilization; employed sequential atomization at 1700°C (Cd) and 2600°C (Fe).

Main Results:

• Achieved characteristic masses of 0.9 pg for Cd and 1.2 ng for Fe.
• Obtained limits of detection of 0.6 µg kg⁻¹ for Cd and 0.5 mg kg⁻¹ for Fe.
• Demonstrated method accuracy by analyzing certified reference materials, with results in agreement at a 95% confidence interval.

Conclusions:

• The developed HR-CS ETAAS method is suitable for routine, quasi-simultaneous determination of Cd and Fe in grain products.
• The method provides satisfactory precision (RSD 3-13%) and accuracy for quality control.
• Analysis revealed Cd levels within acceptable ranges but indicated that most grain products did not meet the legal minimum iron content requirement.