Determination of Mineral Oil Hydrocarbons in Rice and Noodles using LC-GC Online Technique

Significance of the Topic

Food contamination by mineral oil saturated and aromatic hydrocarbons is widespread due to packaging inks and production processes. Their potential to accumulate in the body and possible carcinogenicity spotlights the need for accurate monitoring. Regulatory bodies in Europe are moving toward defined limits and standardized analysis protocols.

Objectives and Study Overview

This study evaluates an online LC-GC hyphenation technique for quantifying MOSH and MOAH in dry foods such as rice and noodles. It aims to simplify sample preparation, increase throughput, and provide robust routine analysis in compliance with emerging standards.

Methodology and Instrumentation

An automated normal phase HPLC pre-separation isolates MOSH and MOAH fractions from interfering compounds. The system couples a Shimadzu Nexera LC platform to a GC-2030 with dual FID detectors. Key features include:

• LC-20ADXR pumps and CBM-20A system controller
• SPD-20A UFLC UV detector for compound monitoring
• PAL autosampler and CHRONOS software for full automation
• On-line HPLC–GC interface eliminating manual cleanup

Main Results and Discussion

The method delivered sensitive detection and reliable quantification in dry food matrices. Spaghetti samples showed a MOSH concentration of 12.7 mg/kg in the C16–C35 range, and rice extracts revealed natural odd-numbered alkanes from C21 to C35. Automated separation effectively removed wax esters and paraffins, yielding clear chromatographic profiles for both MOSH and MOAH fractions.

Benefits and Practical Applications

• High sample throughput with minimal manual steps
• Reduced solvent use and lower risk of GC contamination
• Improved reproducibility and accuracy in routine testing
• Compliance with proposed European standards for MOSH/MOAH analysis

Future Trends and Potential Applications

Advancements may include extending the technique to fatty matrices, integrating mass spectrometry for enhanced selectivity, and harmonizing methods for international regulatory acceptance. Further optimization could target lower detection limits and real-time monitoring in production lines.

Conclusion

The LC–GC–FID online approach offers a fast, robust, and fully automated solution for routine analysis of mineral oil hydrocarbons in dry foods. It meets regulatory requirements and facilitates high-throughput quality control in food safety laboratories.

References

[1] EFSA Journal 2012;10(6):2704 Mineral Oil Hydrocarbons in Food
[2] Commission Recommendation (EU) 2017/84 of 16 January 2017
[3] EN 16995:2017 Determination of MOSH and MOAH by on-line HPLC–GC–FID
[4] Bundesinstitut für Risikobewertung Method for mineral oil hydrocarbons