Thermo Scientific Liquid Chromatography Systems

Importance of the topic

Light absorbance detection in HPLC and UHPLC is fundamental for quantitative and qualitative analysis.
High sensitivity and low noise are critical for trace detection.
LightPipe waveguide technology extends optical path length while minimizing dispersion and baseline noise, addressing key limitations of conventional flow cells.

Objectives and overview

This study evaluates the performance of the Vanquish DAD HL with LightPipe flow cells integrated into the UltiMate 3000 system.
Comparisons include conventional DAD cells of varying path lengths and volumes under UHPLC and HPLC conditions.

Methodology and instrumentation

The UltiMate 3000 RS system was configured with either Vanquish DAD HL or conventional DAD detectors.

• Columns
  
  • Hypersil GOLD C18 2.1 x 100 mm 1.9 µm (UHPLC)
  • Acclaim C18 4.6 x 150 mm 3 µm (HPLC)
• Flow cells
  
  • LightPipe 10 mm path, 2 µL volume
  • LightPipe 60 mm path, 13 µL volume
  • Conventional 7 mm path, 2.5 µL volume
  • Conventional 10 mm path, 13 µL volume
• Flow rates 0.7 mL/min (UHPLC), 2.2 mL/min (HPLC)
• Detection settings 254 nm, 4 nm slit, 20 Hz, 0.2 s response time

Main results and discussion

• The 10 mm LightPipe flow cell produced 30–40 percent higher and narrower peaks versus a 7 mm conventional cell in UHPLC, due to optimized waveguide geometry.
• The 60 mm LightPipe increased peak heights nearly sixfold in HPLC with slight band broadening but improved signal-to-noise compared to a 10 mm conventional cell.
• LightPipe design reduces refractive index induced baseline disturbances during gradients, yielding smoother baselines than conventional designs.
• Signal-to-noise ratios improved by factors of 2–4 (10 mm cell) and 5–14 (60 mm cell) relative to conventional cells, enabling enhanced trace detection.

Benefits and practical applications

LightPipe technology enables superior sensitivity for trace level quantitation in HPLC and UHPLC.
Its robust performance under gradient conditions and minimal baseline drift make it suitable for complex matrices in pharmaceutical, environmental, and biochemical analysis.

Future trends and opportunities

• Development of advanced waveguide materials to further lower noise and extend path length.
• Integration with high throughput UHPLC workflows for omics and environmental testing.
• Application to multi wavelength array detection for real time peak purity assessment.
• Miniaturization for microflow and nano flow applications to further reduce sample consumption.

Conclusion

LightPipe waveguide technology in the Vanquish DAD HL on UltiMate 3000 platforms sets a new standard for UV detection.
By combining extended optical path length with minimized dispersion and noise, it delivers unparalleled sensitivity and robustness for routine and trace analysis.

References

• Thermo Fisher Scientific SP71543 EN 0315S Thermo Scientific Liquid Chromatography Systems The Latest LightPipe Technology for the UltiMate 3000 Platform 2015