Agilent RoHS Compliant Ion Injector for LC/MS Single Quadrupole and Triple Quadrupole Instruments

Importance of the Topic

The Restriction of Hazardous Substances (RoHS) directive is driving the replacement of legacy components in analytical instruments with materials that comply with environmental regulations. In liquid chromatography–mass spectrometry (LC–MS), the ion injector is a critical element for efficient ion transfer, desolvation and focusing. Ensuring that a RoHS-compliant ion injector matches the performance of its legacy counterpart is essential for pharmaceutical, environmental and clinical laboratories that require both regulatory adherence and uncompromised analytical quality.

Objectives and Study Overview

The primary goal of this study was to compare the analytical performance of a newly developed RoHS-compliant ion injector against the existing legacy capillary injector on two Agilent LC–MS platforms. Key performance indicators included tuning stability, chromatographic retention, method sensitivity (accuracy, precision, limits of detection and quantitation) and robustness in both standard solutions and a complex biological matrix (human urine).

Methodology

Two analytical workflows were established:

• Single-quadrupole quantitative analysis (SIM) of nine pharmaceuticals in neat solvent at 10 and 100 ppb using an Agilent Infinity II LC coupled to an MSD iQ (G6160A).
• Triple-quadrupole quantitation (MRM) of the same analytes spiked into human urine (10:1 dilution) at low-ppt levels (5–1000 ppt) using an Agilent Infinity II LC and an Ultivo TQ (G6465B).

Both methods employed a binary gradient (0.1% formic acid in water vs acetonitrile), positive-ion electrospray, and standardized fragmentor/collision energies. Calibration curves (eight points) exhibited R² > 0.995 on both injectors. Method validation followed typical pharmaceutical acceptance criteria: accuracy within 80–120% and precision < 5% RSD for ppb-level; precision < 10% RSD for ppt-level assays.

Instrumentation

Equipment and part numbers:

• Agilent Infinity II LC system: binary pump, multisampler, column compartment.
• Single quadrupole: MSD iQ (G6160A).
• Triple quadrupole: Ultivo TQ (G6465B).
• RoHS injectors: G3911-30000 (0.6 mm FS) and G3911-30001 (ID 180 mm).
• Legacy injectors: G1960-80060 and G6301-80004.

Pharmaceutical standards and solvents were obtained from certified suppliers; human urine was diluted 10:1 in 0.1% formic acid.

Main Results and Discussion

Both RoHS and legacy injectors passed ten consecutive autotunes without significant tuning parameter differences. Chromatograms showed equivalent retention and peak shape. In the single-quad SIM workflow:

• Accuracy at 10 and 100 ppb ranged 92–106% for RoHS vs 86–105% for legacy.
• Precision was < 1.7% RSD at 10 ppb and < 0.7% RSD at 100 ppb on both injectors.
• Instrument detection limits at 10 ppb were of the same order; fluoxetine displayed an improved IDL on the RoHS injector (0.83 ppb vs 3.87 ppb).

In the Ultivo MRM workflow:

• Limits of detection were < 2.6 ppt and LOQs < 8.4 ppt, with nearly identical values on both injectors.
• Accuracy at 10 ppt remained within 97–101% and at 100 ppt within 99–107%.
• Precision at 10 ppt was < 9% RSD and at 100 ppt < 2.3% RSD for all analytes.

Overall, the RoHS injector matched or exceeded legacy performance across all validation metrics.

Benefits and Practical Applications

The RoHS-compliant ion injector offers:

• Full adherence to environmental regulations without loss of analytical performance.
• Seamless integration into existing LC–MS platforms (single and triple quadrupole).
• Consistent tuning stability and high reproducibility for regulated pharmaceutical and bioanalytical workflows.

Laboratories can adopt the RoHS injector as a direct replacement, ensuring future compliance and uninterrupted quality control.

Future Trends and Applications

As regulatory pressures increase, manufacturers will expand RoHS-compliant components across other ionization sources and mass spectrometer models. Ongoing developments may include:

• Green chemistry approaches to MS consumables.
• Ion injector designs optimized for emerging high-throughput and high-resolution platforms.
• Integration with automated cleaning and maintenance protocols to further boost uptime.

Conclusion

This study demonstrates that the newly designed RoHS-compliant ion injector performs on par with the legacy capillary in both single-quad and triple-quad LC–MS workflows. With equivalent sensitivity, accuracy and precision, the RoHS injector can replace legacy models, supporting laboratories in meeting environmental requirements without sacrificing analytical quality.