High-Speed Analysis of Total Petroleum Hydrocarbons (TPH) using Brevis GC-2050

Significance of High-Speed TPH Analysis

Total petroleum hydrocarbons (TPH) are complex mixtures of hydrocarbons that can persist in water and soil, posing environmental and health risks. Rapid and reliable monitoring of TPH levels is critical for regulatory compliance, pollution control and risk assessment in environmental and industrial settings. High-throughput analytical methods reduce turnaround time, increase laboratory productivity and enable timely decision-making in contamination events.

Objectives and Study Overview

This study demonstrates a rapid gas chromatographic method for quantifying TPH in line with ISO 9377-2:2000 requirements. Using the compact Brevis GC-2050 with dual injectors and hydrogen carrier gas, the authors aimed to shorten the analysis time to under 6 minutes while maintaining resolution, repeatability and calibration linearity across C10 to C40 hydrocarbons.

Experimental Methodology

The procedure comprised three sample types:

• Solvent/background correction sample: heptane.
• System performance test sample: 50 µg/mL alkane standard mixture (n-alkanes C10–C40).
• Calibration curve samples: mineral oil solutions prepared by diluting a QC standard (5 000 µg/mL) to 50–1 000 µg/mL in heptane, with internal standards n-tetracontane (C40) and n-decane (C10).

Chromatographic parameters were optimized for speed:

• Column: SH-I-1-1MS, 12 m × 0.2 mm I.D. × 0.33 µm film.
• Carrier gas: hydrogen at 7.00 mL/min (column flow).
• Oven program: 100 °C (0.3 min) → 175 °C at 65 °C/min → 300 °C at 45 °C/min → 340 °C at 35 °C/min (0.5 min).
• Injection: split mode (1 µL, split ratio 1:5) at 280 °C using dual AOC-30i auto-injectors.
• Detector: flame ionization detector (FID) at 350 °C with H₂ (32 mL/min), air (200 mL/min) and N₂ makeup (24 mL/min).

Used Instrumentation

• Sigma-Aldrich alkane standard mixture, P/N 94234-2ML.
• Sigma-Aldrich QC standard solution, P/N 51706-1ML.
• Shimadzu Brevis GC-2050 gas chromatograph (230 V) with dual AOC-30i auto-injectors.
• SH-I-1-1MS capillary column (P/N 227-36004-03).
• Xtra Life microsyringe (P/N 227-35400-01).

Results and Discussion

System performance testing with a 50 µg/mL alkane standard showed baseline separation of C10 from heptane within 0.4 minutes. The C40/C20 peak area ratio exceeded 0.94, meeting the ISO 9377-2 criterion of ≥ 0.8. Peak area repeatability for C20 and C40 was better than 0.5 % RSD.

Calibration curves constructed over 50–1 000 µg/mL yielded excellent linearity (R² ≥ 0.9998) on both analysis lines. RSD values for mineral oil average areas ranged from 0.12 % to 1.09 % across concentrations, demonstrating high precision.

Practical Benefits of the Method

• Analysis time reduced to under 6 minutes for full C10–C40 range.
• High throughput enabled by dual injectors and fast oven programming.
• Space-saving compact GC model suitable for routine environmental labs.
• Hydrogen carrier gas accelerates elution and sharpens peaks without compromising resolution.

Future Trends and Opportunities

Advances in column technology and ultra-fast temperature programming are expected to further decrease analysis times and broaden the detectable hydrocarbon range. Integration with automated sample preparation and data processing platforms could enable near real-time monitoring of environmental samples. The application of alternative detectors or multidimensional GC may enhance selectivity for complex mixtures and regulatory compliance.

Conclusion

The Brevis GC-2050 with hydrogen carrier gas and rapid temperature ramping provides a robust, high-speed solution for TPH analysis in accordance with ISO 9377-2. Achieving complete separation of C10–C40 hydrocarbons within 6 minutes, the method combines precision, linearity and productivity, making it well suited for environmental and industrial laboratories.

Reference

• ISO 9377-2:2000, Water quality – Determination of hydrocarbon oil index – Part 2: Method by gas chromatography.
• Shimadzu Application News 01-00355-JP, “High-Speed Analysis of Total Petroleum Hydrocarbons (TPH)”.
• Shimadzu Application News 01-00562-EN, First Edition Sep. 2023.