Determination of Mineral Oil in Water According to ISO 9733-2:2000 Using ISOLUTE® Na2SO4/FL Solid Phase Extraction Columns

Importance of the topic

Measuring mineral oil contamination in water is essential to monitor environmental pollution, ensure compliance with regulatory standards, and protect aquatic ecosystems and human health from hydrocarbon exposure.

Objectives and study overview

This application note outlines the procedure for quantifying mineral oil in water following ISO 9377-2:2000. It combines liquid-liquid extraction with hexane and a solid-phase extraction cleanup using ISOLUTE Na2SO4/FL columns to isolate hydrocarbons from aqueous samples.

Methodology and instrumentation

The workflow includes:

• Sample conditioning: cooling to 10 °C, acidification to pH 2, and addition of magnesium sulfate.
• Liquid-liquid extraction with hexane, shaking or stirring for 30 minutes.
• SPE cleanup using sodium sulfate/florisil columns, with hexane elution under gravity or low pressure.
• Post-extraction concentration: rotary evaporation to ~6 mL, nitrogen blowdown to 1 mL, and volume adjustment for GC analysis.

Instrumentation and reagents include a rotary evaporator, nitrogen evaporator, gas chromatograph, hexane, magnesium sulfate, and hydrochloric acid for sample preparation.

Main results and discussion

The dual-layer SPE effectively removes water and polar interferences, yielding clean hexane extracts. The method delivers high recovery rates, reproducible results, and compatibility with GC analysis, meeting ISO sensitivity and precision criteria.

Advantages and practical applications

• Simplified protocol suitable for field and laboratory use.
• High selectivity enhances accuracy of hydrocarbon measurement.
• Adaptable to varying sample volumes and different GC injection setups.
• Applicable in environmental monitoring, industrial quality control, and regulatory compliance testing.

Future trends and potential applications

Advancements may include automated SPE platforms, microscale extraction techniques, alternative sorbent materials, and direct coupling to mass spectrometry. These innovations aim to streamline workflows, reduce solvent consumption, and expand application to complex matrices.

Conclusion

The ISO 9377-2:2000 method using ISOLUTE Na2SO4/FL SPE columns provides a reliable and efficient approach for determining mineral oil in water, ensuring robust cleanup and accurate GC quantification aligned with regulatory standards.

Reference

1. ISO 9377-2:2000 Determination of hydrocarbon oil index Part 2: Method using solvent extraction and gas chromatography.