Fast and efficient analysis of mineral oil in environmental samples according to H53

Significance of the topic

Mineral oil hydrocarbons (MOH) from crude oil derivatives frequently contaminate soil and water and pose persistent environmental hazards due to their resistance to biodegradation. Monitoring MOH levels in drinking water, surface water and wastewater is essential for environmental protection and regulatory compliance.

Objectives and Study Overview

This study demonstrates a fast, reliable method for quantifying MOH in environmental samples following the European standard EN ISO 9377-2 (H53). It compares split/splitless (SPL) injection performance to on-column injection, evaluates the use of hydrogen carrier gas, and applies the optimized method to real water samples.

Methodology and Instrumentation

Sample Preparation

• Water samples extracted and purified on Florisil to remove polar interferences.
• Quantification by integrating FID responses between n-decane (C10) and n-tetracontane (C40), covering boiling points 175–525 °C.
• Use of external MOH standards (diesel/lubricating oil mixtures) for calibration.

Instrumentation

• Nexis GC-2030 gas chromatograph with SPL-2030 injector and flame ionization detector.
• SH-Mxt-1 capillary column (15 m × 0.25 mm ID, 0.1 μm film) with Uniliner retention gap.
• Hydrogen as carrier gas at 80 cm/s to reduce analysis time.

Results and Discussion

SPL injection proved essentially non-discriminatory with an area ratio C40/C20 above 0.96, meeting ISO 9377-2 requirements. With helium carrier gas, C40 eluted at 7.8 min and full run completed in under 9 min. Switching to hydrogen reduced run times to under 6 min while maintaining C40/C20 above 0.90. Calibration in ranges 0–1.5 mg/mL and 0–10 mg/mL yielded correlation coefficients > 0.9998. Analysis of real samples showed MOH levels within the calibrated ranges.

Benefits and Practical Applications

The optimized method significantly accelerates MOH analysis, increasing sample throughput while ensuring compliance with H53 standards. Use of SPL injection simplifies maintenance, and hydrogen carrier gas further enhances speed without loss of resolution. This approach is well suited for environmental monitoring laboratories and quality control in water treatment.

Future Trends and Opportunities

Adoption of fast GC methods with alternative carrier gases may extend to other complex hydrocarbon mixtures. Integration with mass spectrometric detection could provide additional selectivity and compound identification. Continuous improvements in injector technology and column materials will further enhance accuracy and throughput.

Conclusion

The validated GC-FID method using a SPL injector on the GC-2030 offers fast, robust quantification of MOH in environmental water samples in accordance with EN ISO 9377-2. Implementation of hydrogen carrier gas reduces run times to as little as 6 minutes, increasing laboratory efficiency without compromising analytical performance.

Reference

EN ISO 9377-2: Water quality — Determination of hydrocarbon oil index — Part 2: Method using gas chromatography