Increased Sample Throughput and Capacity for Online SPE Enrichment

Importance of the Topic

Online solid-phase extraction (SPE) coupled directly to liquid chromatography–tandem mass spectrometry enables rapid, sensitive detection of trace-level contaminants in environmental waters. Automating large-volume injections and wash steps reduces manual handling, minimizes carryover, and ensures reliable quantification at sub-ng/L levels.

Objectives and Study Overview

This overview evaluates the integration of an Agilent 1260 Infinity Multisampler equipped with a 900 µL loop and multiwash options with an Agilent 1200 Infinity Series online SPE system. The main objectives are to enhance sample throughput, maximize vial capacity, and demonstrate robust performance for the analysis of herbicides in tap, river, and ground water.

Methodology and Instrumentation

The workflow combines online SPE enrichment, large-volume injection, and triple quadrupole MS detection. Key instruments include:

• Agilent 1260 Infinity Multisampler with 900 µL loop, multiwash feature, thermostatted cooler (10 °C), and dual-height drawers for up to 60 × 6 mL and 108 × 2 mL vials
• Agilent 1200 Infinity Series online SPE solution with solvent selection valve, flush pump, seat backflush, and metering devices (40, 100, 900 µL)
• Agilent 1260 Infinity Binary Pump and Thermostatted Column Compartment
• Agilent 6490 Triple Quadrupole LC/MS with Jet Stream technology

The SPE method uses water/0.1 % formic acid and acetonitrile/0.1 % formic acid gradient on a ZORBAX SB-Aq column (2.1 × 100 mm, 3.5 µm), 0–900 µL injection volume, and a multiwash needle cleaning cycle.

Main Results and Discussion

Validation in tap, river, and ground water spiked at 0.1–50 ng/L demonstrated:

• Excellent linearity (R² > 0.997) across calibration levels
• Recoveries of 82 %–106 % and area precision (RSD) < 5 % for standards, < 10 % in environmental matrices
• Limits of detection between 0.003 and 0.5 ng/L and LOQs of 0.01–1 ng/L from a single 900 µL injection
• Minimal matrix effects and no observable carryover due to multiwash configuration

Apparent recoveries for herbicides in spiked water samples consistently fell within 70–130 %, confirming reliable quantification in complex matrices.

Benefits and Practical Applications

This integrated system increases sample throughput by accommodating up to 168 samples per worklist, reduces hands-on preparation time, and enhances sensitivity for trace analysis. It is well suited for environmental monitoring, regulatory compliance testing, and high-volume routine analysis in pharmaceutical, food, and water industries.

Future Trends and Potential Applications

Emerging developments include coupling online SPE with high-resolution MS for non-target screening, further miniaturization of cartridges, integration with robotic autosamplers for fully automated workflows, and application to a wider range of analytes such as emerging contaminants and biomarkers.

Conclusion

The combination of the Agilent 1260 Infinity Multisampler with a 900 µL loop and an online SPE system offers robust, high-throughput trace analysis with excellent precision and negligible carryover. This configuration streamlines environmental water testing and supports reliable quantification at sub-ng/L levels.

References

1. Huesgen A., Schneider S. Performance Characteristics of the Agilent 1290 Infinity II Multisampler. Agilent Technologies Technical Overview, Publication 5991-5348EN (2014).
2. Yang D., Naegele E. Detection of Basic and Acidic Pesticides and Herbicides at Trace Levels by Online SPE LC/MS in Drinking Water. Agilent Technologies Application Note 5991-4177EN (2014).
3. Naegele E. Quantification of Trace-Level Herbicides in Drinking Water by Online Enrichment with the Agilent 1200 Infinity Series Online SPE Solution and Triple Quadrupole MS Detection. Agilent Technologies Application Note 5991-1738EN (2013).
4. Anumol T., Snyder S.A. Rapid Analysis of Trace Organic Compounds in Water by Automated Online Solid-Phase Extraction Coupled to LC–MS/MS. Talanta, 132, 77-86 (2015).