Meeting NJ Low Level TO-15 Air Testing Method Requirements

Significance of the Topic

The New Jersey Low Level TO-15 method enhances detection of trace volatile organic compounds in air, critical for environmental site remediation and regulatory compliance. By lowering reporting limits and reinforcing quality controls, it supports accurate risk assessment and mitigation at contaminated sites.

Study Objectives and Overview

This study evaluates the performance of a Markes Unity with CIA Advantage preconcentrator combined with a 30 m Rtx-VMS column and Agilent 7890B-5977A GC-MS system in meeting the New Jersey DEP Site Remediation Program Low Level TO-15 method requirements. Key goals include verifying chromatography, calibration precision, detection limits, accuracy, and carryover for up to 75 target VOCs.

Methodology

The analytical workflow consists of:

• Sample collection: 250 mL canister samples spiked with internal standard mix.
• Preconcentration: Thermoelectric trap cooling/heating from –30 °C to 425 °C without liquid nitrogen; split purge to remove water and major gases.
• Gas chromatography–mass spectrometry: 30 m Rtx-VMS column, helium carrier gas, oven ramp from 32 °C to 230 °C.
• Calibration: Six-point curve from 0.2 to 40 ppbv using 75-component standard.
• Performance tests: Method detection limit (MDL), precision (seven replicates at 0.2 ppbv), audit accuracy (10 ppbv standard), and carryover experiments.

Instrumentation Used

• Preconcentrator: Markes Unity with CIA Advantage canister interface.
• Gas chromatograph: Agilent 7890B.
• Mass spectrometer: Agilent 5977A single quadrupole.
• Analytical column: Rtx-VMS, 30 m × 0.25 mm ID, 1.40 µm film.
• Internal standards: TO-14A mix and 75-component TO-15 + NJ mix.

Main Results and Discussion

Chromatography on the 30 m Rtx-VMS column achieved baseline separation of 75 EPA and NJ target VOCs in a 22-minute run, with only a minor coelution of chloromethane and n-butane manageable through ion selection. Calibration response factors showed an average RSD of 14.8%—well within the 30% limit. MDLs averaged 0.101 ppbv, satisfying the 0.20 ppbv threshold for all but acetone and tertiary butyl alcohol, for which method allowances apply. Precision averaged 13.3% RSD and audit accuracy averaged 7.6%, meeting the ±30% requirement. Carryover was negligible in routine samples (<0.03%) and acceptable even after high-level injections (<0.17%), provided high concentration runs are sequenced last with conditioning blanks.

Benefits and Practical Applications

This configuration delivers reliable low-level VOC analysis for site remediation, industrial monitoring, and QA/QC laboratories. It eliminates liquid nitrogen requirements, reduces analysis time with a simple oven program, and demonstrates robust real-world performance using aged sources and auto-integration.

Future Trends and Potential Applications

• Optimizing trap materials and column phases to further improve separation of polar VOCs.
• Integrating fast GC techniques and high-resolution MS for expanded analyte coverage.
• Automating calibration and quality checks to enhance throughput in routine monitoring.
• Applying similar low-level methods to emerging contaminants, such as semi-volatile organics and novel halogenated compounds.

Conclusion

The Markes Unity with CIA Advantage preconcentrator paired with a 30 m Rtx-VMS column and Agilent GC-MS meets all critical requirements of the New Jersey Low Level TO-15 air testing method. The system provides precise, accurate, and sensitive analysis of a comprehensive VOC suite under realistic laboratory conditions.

References

1. U.S. Environmental Protection Agency. Compendium Method TO-15, Determination of volatile organic compounds in air collected in canisters and analyzed by GC-MS. EPA/625/R-96/010b, January 1999.
2. Herrington, J.S. Rapid determination of TO-15 volatile organic compounds in air. Restek Application Note EVAN1725B-UNV, 2016.
3. New Jersey Department of Environmental Protection. Site Remediation Program Low Level USEPA Method TO-15, March 2007.
4. Klee, M.S., Blumberg, L.M. Theoretical and practical aspects of fast gas chromatography and method translation. Journal of Chromatographic Science, 40(5):234–247, 2002.