Determination of Arsenic Species in Apple Juice by LC-ICP-MS Analysis

Importance of the Topic

The presence of arsenic in food products is a critical public health concern, as toxicity depends on its chemical form. Inorganic species such as arsenite (As III) and arsenate (As V) are more harmful than organic forms. Reliable speciation analysis in apple juice helps ensure compliance with regulatory action levels and protects consumers.

Objectives and Study Overview

This study demonstrates the determination of six arsenic species in commercially available apple juice using an online LC-ICP-MS system. The goal is to achieve sensitive, accurate quantitation of each species and verify compliance with the FDA action level of 10 µg/kg for inorganic arsenic.

Methodology

Sample pretreatment involved diluting 2 mL of apple juice with phosphoric and nitric acids to 10 mL. Calibration standards of As III, As V, MMA, DMA, AsB, and AsC were prepared in nitric acid. The mobile phase comprised 0.1 % formic acid with 1 % methanol and 0.025 % tetramethylammonium hydroxide. A column stabilizer solution was circulated before analysis to ensure retention stability.

Used Instrumentation

• Nexera™ series HPLC with Sigma–Aldrich Discovery HS F5 column (250 mm×4.6 mm, 5 µm) and Shim-pack™ GIST guard column
• Shimadzu ICPMS-2040/2050 quadrupole ICP-MS with Mini-Torch, electronically cooled cyclone chamber, He collision gas, and DC04 nebulizer
• LabSolutions™ ICPMS TRM software for unified control of LC and ICP-MS

Main Results and Discussion

Chromatograms exhibited baseline separation of all six species within a 6 min runtime. Calibration curves were linear from 0.2 to 10 µg/L (R² > 0.999). Instrument detection limits (3σ) ranged from 0.02 to 0.04 µg/L, confirming suitability for trace-level analysis. Spike recovery rates were 101–106 %, and native concentrations of As III and As V in the juice were 0.18 and 0.08 µg/L, respectively; organic species were near or below detection.

Benefits and Practical Applications

The integrated LC-ICP-MS workflow enables rapid, high-sensitivity speciation of arsenic in food matrices. It simplifies regulatory testing by using a method package that eliminates manual condition setup, supporting quality control in food safety laboratories.

Future Trends and Prospects

Advances in chromatography and mass spectrometry, such as multicollector ICP-MS and high-resolution separation media, will further improve detection limits and throughput. Expanding speciation methods to other food matrices and environmental samples will enhance risk assessment and monitoring strategies.

Conclusion

The LC-ICP-MS system effectively quantifies six arsenic species in apple juice with minimal sample preparation. Sensitivity and precision meet regulatory requirements, demonstrating that the tested juice contains inorganic arsenic levels well below the FDA action level.

References

1. FDA Final Guidance to Industry on Action Level for Inorganic Arsenic in Apple Juice, June 8, 2023.
2. FDA Guidance for Industry: Action Level for Inorganic Arsenic in Apple Juice, June 8, 2023.