Automated Sample Preparation Using the PAL3 RTC System for EPA 8270E Semivolatile Organic Analysis by GC/TQ

Importance of the Topic

Semivolatile organic compounds (SVOCs) pose significant environmental and health risks and require sensitive and reliable analytical methods. Conventional manual sample preparation workflows are labor-intensive, time-consuming, and solvent-intensive, leading to throughput limitations and variability in results. Automating sample preparation can streamline operations, enhance reproducibility, reduce solvent usage, and improve laboratory productivity and sustainability.

Objectives and Study Overview

This study aimed to develop and evaluate an automated workflow for the quantitation of 100 SVOCs in water samples. The approach integrates calibration standard preparation, liquid-liquid extraction (LLE), and GC/triple quadrupole mass spectrometry (GC/TQ) analysis based on EPA 8270E and a modified EPA 3510C protocol, using the PAL3 RTC system. The system was assessed for calibration performance, method sensitivity, blank control, and recovery in quality control (QC) samples.

Methodology and Instrumentation

Ultrafast automated calibration and extraction were performed on a PAL3 Series II robotic tool change (RTC) system equipped with vortex mixing, solvent and wash modules, and PTFE-coated syringes. A stock mixture of target analytes (300 µg/mL) and an internal standard mix (40 ppm) in dichloromethane were loaded onto the PAL3. The system prepared 10 calibration levels (0.01–20 µg/mL) by automated dilution and spiked each with 5 µL of internal standard.
Water samples (15 mL) were manually preloaded with 1 g NaCl, then processed by the PAL3 in sequential LLE steps: pH adjustment, two DCM extractions, phase separation, extract pooling, internal standard addition, and vortex mixing. Final extracts (250 µL) were directly injected (2 µL) into the GC/TQ.

Used Instrumentation

• Agilent 8890 gas chromatograph with DB-UI8270D column (30 m × 0.25 mm × 0.25 µm)
• Agilent 7000 series triple quadrupole mass spectrometer (dMRM mode, EI ionization)
• PAL3 Series II RTC liquid handling platform
• Agilent MassHunter Workstation GC/MS Data Acquisition 10.1 software

Main Results and Discussion

Online operation allowed parallel sample preparation and analysis, maximizing throughput. Calibration data (0.01–20 µg/mL) showed excellent linearity (96 % of analytes r2>0.995), accuracy (97 % within fixed limits), and response factor RSD<20 %. Method sensitivity (LLOQ) for 100 analytes ranged from 0.01 to 0.5 µg/mL, with 39 compounds ≤0.02 µg/mL. Method blanks confirmed contamination control (<50 % of LLOQ). Matrix-spiked QC recovery at 2 µg/mL yielded 96 % of compounds between 50–150 % recovery and 98 % with RSD≤20 %, demonstrating robustness and reproducibility.

Benefits and Practical Applications

Automating sample preparation via the PAL3 reduces manual labor, standard and solvent consumption, and waste generation. The integrated PAL3-GC/TQ solution enhances throughput, data quality, and consistency, supporting high-volume environmental monitoring, QA/QC, and regulatory compliance applications.

Future Trends and Opportunities

Further developments may include miniaturized extraction techniques, integration with other sample preparation modules, on-line derivatization, coupling with high-resolution mass spectrometers, and AI-driven method optimization. Green chemistry approaches and real-time data processing can further improve sustainability and laboratory efficiency.

Conclusion

The automated workflow combining the PAL3 RTC system with Agilent 8890/7000 GC/TQ instruments meets EPA 8270E performance criteria for SVOC analysis in water. It delivers reliable calibration, high sensitivity, robust blank control, and consistent recoveries while significantly reducing manual work and solvent use, ultimately improving laboratory productivity and environmental sustainability.

References

• EPA Method 8270E: Semivolatile Organic Compounds by GC/MS, Revision 6, June 2018
• EPA Method 3510C: Separatory Funnel Liquid-Liquid Extraction
• Agilent application note 5994-0691EN: “A Fast Method for EPA 8270 in MRM Mode Using the 7000 Series Triple Quadrupole GC/MS,” 2019