Inorganic arsenic in seafood: does the extraction method matter?

Area of Science:

• Analytical Chemistry
• Environmental Science
• Food Safety

Background:

• Accurate measurement of inorganic arsenic (iAs) in seafood is crucial for human health risk assessment.
• Seafood composition can influence the efficiency of various extraction methods for trace elements.
• Standardized methods are needed to ensure reliable and comparable iAs data across studies.

Purpose of the Study:

• To evaluate the influence of nine different extraction methods on inorganic arsenic (iAs) determination in seafood.
• To compare iAs concentrations obtained using various methods in certified reference materials (CRMs) and a commercial fish meal.
• To identify extraction methods that provide the most accurate and reproducible iAs measurements in seafood.

Main Methods:

• Evaluation of nine distinct extraction protocols for seafood samples.
• Analysis of inorganic arsenic (iAs) concentrations using certified reference materials (DOLT-4 and TORT-2) and a herring fish meal.
• Standardized experimental conditions with a single operator and instrumentation to minimize laboratory-induced variability.

Main Results:

• Low concentrations of inorganic arsenic (iAs) were consistently found in DOLT-4 and herring fish meal across all extraction methods.
• CRM TORT-2 showed significant differences in iAs extraction, with dilute nitric acid (HNO3) and hydrochloric acid (HCl) yielding higher concentrations.
• Dilute sodium hydroxide (NaOH) in 50% ethanol resulted in significantly lower extracted iAs from TORT-2 compared to acidic methods; other solvents showed no significant differences.

Conclusions:

• The choice of extraction method critically affects inorganic arsenic (iAs) quantification in certain seafood matrices, notably TORT-2.
• Acidic extraction solvents (HNO3, HCl) appear more effective for extracting iAs from lobster hepatopancreas compared to alkaline solvents.
• Method-dependent variability in iAs determination necessitates careful selection of extraction protocols for accurate seafood analysis and risk assessment.