Inorganic arsenic speciation analysis in food using HPLC/ICP-MS: Method development and validation

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Food Science

Background:

• Inorganic arsenic (iAs) is more toxic than organic arsenic and can accumulate in food from contaminated environments.
• Regulatory bodies have established iAs limits in staple foods like rice, seaweed, seafood, and marine oils to protect public health.
• Accurate and selective analytical methods are crucial for monitoring iAs levels in diverse food matrices.

Purpose of the Study:

• To develop and validate a robust analytical method for the selective determination of inorganic arsenic (iAs) in various food types.
• To assess the efficacy of the developed method in quantifying iAs in rice, seaweed, seafood, and marine oils.
• To conduct surveillance studies on iAs content in commercially available food products.

Main Methods:

• Combined High-Performance Liquid Chromatography/Inductively Coupled Plasma-Mass Spectrometry (HPLC/ICP-MS) was employed for iAs speciation.
• Extraction of iAs from food matrices was performed using a nitric acid and hydrogen peroxide solution under sonication.
• Oxidation of As(III) to As(V) prior to HPLC/ICP-MS analysis prevented chromatographic interferences.

Main Results:

• The developed HPLC/ICP-MS method demonstrated high extraction efficiencies (>90%) and low limits of quantification (0.02 mg/kg in fish oil).
• Method validation across various food matrices (rice, seaweed, seafood, marine oil) showed excellent average recoveries (87.5–112.4%) and precision (<10% CV).
• Market surveillance revealed only Hijiki seaweed exceeded the regulatory limit for iAs; other samples complied with standards.

Conclusions:

• The validated HPLC/ICP-MS method provides a quick, straightforward, and reliable approach for routine iAs analysis in a wide range of food products.
• The method effectively safeguards public health by ensuring compliance with established iAs safety standards in the food supply.
• Findings underscore the importance of continued monitoring, particularly for specific seaweeds like Hijiki, regarding inorganic arsenic contamination.