Requirements of an Automated Sample Delivery System in Today’s Realm of Ever Increasing Sensitivity Demands Utilizing the Atomx Concentrator/Multimatrix Autosampler

Importance of the Topic

As analytical instrumentation reaches ever higher sensitivity, controlling sample carryover becomes critical to ensure data integrity and maintain instrument performance. Automated sample delivery systems designed for volatile analyses must minimize cross-contamination, reduce downtime for cleaning, and meet regulatory requirements. Evaluating new autosampler technologies under realistic workflows supports robust environmental and industrial monitoring.

Objectives and Overview

This study assesses the carryover performance of the Atomx concentrator/autosampler coupled to a GC/MS system. Key goals include:

• Measuring residual analyte levels in blanks following high-concentration (200 ppb) standards in water and soil matrices
• Comparing rinse strategies using heated water and methanol in various sequences and volumes
• Demonstrating improvements over traditional standalone purge-and-trap setups

Methodology

Calibration standards were prepared in water (0.5–200 ppb) and soil extracts (1–200 ppb) with a 25 ppb internal standard. Samples and blanks were processed automatically by the Atomx, followed by analysis on an Agilent 7890A GC with DB-VRX column and 5975C inert XL mass spectrometer. Carryover was quantified by analyzing three successive blanks after a 200 ppb sample. Various rinse protocols were tested:

• Multiple 90 °C water bake rinses (1–3 cycles)
• Combination of water bake rinse and methanol rinses of the needle or sparge vessel
• Single methanol rinse volumes of 3 mL or 5 mL

Used Instrumentation

• Atomx Concentrator/Multimatrix Autosampler with #9 U-shaped adsorbent trap
• Agilent 7890A Gas Chromatograph
• Agilent 5975C inert XL Mass Spectrometer

Main Results and Discussion

Heating water bake rinses alone achieved moderate carryover reduction, but incorporating a single 3 mL methanol rinse of the sparge vessel lowered carryover of late-eluting compounds by up to 50%. Overall, methanol rinse protocols consistently reduced residuals to below 0.25% after a 200 ppb injection, matching or surpassing standalone concentrator performance. Needle rinses enhanced results in the soil matrix, where coarse particles challenge system cleaning.

Benefits and Practical Applications

• Significant reduction of carryover ensures reliable quantitation in environmental testing and QA/QC workflows
• Automated rinse options decrease manual maintenance and increase sample throughput
• Flexible rinse protocols allow optimization for diverse sample types and concentration ranges

Future Trends and Opportunities

Continued integration of automated sample preparation with advanced detection will drive even higher throughput and lower detection limits. Emerging rinse chemistries and trap materials may further reduce cross-contamination. Remote monitoring and adaptive rinse scheduling based on sample history could optimize instrument uptime.

Conclusion

The Atomx system, combining purge-and-trap concentrator and autosampler, offers a shortened sample path and multiple hot water and methanol rinse options that effectively minimize carryover. Performance meets stringent regulatory criteria, enhancing productivity and data quality in volatile organic analyses.

References

1. USEPA Method 8260B, Volatile Organic Compounds by GC/MS, Revision 2, December 1996