The Cary Sipper—Pump and Measure Multiple Samples Simultaneously

Significance of the Topic

The automated handling of liquid samples in UV-Vis spectroscopy addresses key challenges in modern analytical laboratories, including throughput limitations, reproducibility issues and manual errors. By replacing manual cuvette filling, cleaning and handling steps, the Cary Sipper accessory enhances efficiency and data quality across pharmaceutical, environmental and quality-control applications.

Objectives and Study Overview

This technical overview describes the design and performance of the Agilent Cary Sipper accessory when coupled to the Cary 3500 UV-Vis spectrophotometer. Main goals are to illustrate automation modes, compare sample-throughput improvements against manual methods, and outline the operational parameters that drive accuracy and speed.

Methodology

The Cary Sipper integrates a three-channel peristaltic pump to deliver sample and rinse solutions through flow cells positioned inside the Cary 3500. Two system configurations are possible:

• Compact (single flow cell) with one pump channel and external reference cuvette.
• Multicell (three flow cells) with simultaneous multi-sample measurement and external reference cuvette.

Pumping parameters are controlled via the Cary UV Workstation software:

• Fill time adjustable to sample viscosity.
• Hold time to allow bubble settling before measurement.
• Rinse time to prevent carry-over between analyses.

Throughput was benchmarked by measuring 30 samples over a wavelength range of 200–350 nm, using identical spectral settings (0.1 s averaging, 1 nm data interval, 1 nm bandwidth). Measurements were compared across:

1. Manual single cuvette on Compact.
2. Manual three cuvettes on Multicell.
3. Sipper with one flow cell on Compact.
4. Sipper with three flow cells on Multicell.

Instrumentation Used

• Agilent Cary 3500 UV-Vis spectrophotometer (Compact or Multicell configuration).
• Cary Sipper accessory with three-channel peristaltic pump.
• Peristaltic pump tubing options: PVC, PVC Solva, Marprene.
• Quartz flow cells: 10 mm pathlength, 390 µL and 80 µL volumes.
• Cary UV Workstation software for pump control and temperature regulation.

Main Results and Discussion

Time to analyze 30 samples varied significantly:

• Manual single cuvette (Compact) – 21 min 30 s.
• Manual three cuvettes (Multicell) – 16 min 26 s (24 % faster than single cuvette).
• Sipper + single flow cell – 19 min 32 s (9 % faster).
• Sipper + three flow cells – 7 min 30 s (65 % faster).

The three-cell Sipper configuration delivered the largest time savings while ensuring consistent temperature control and minimizing contamination risks. Automated rinsing and hold steps improved reproducibility by removing manual variability and preventing cross-sample carry-over.

Benefits and Practical Applications

• High throughput: up to three samples measured in parallel.
• Labor savings: eliminates manual cuvette handling and cleaning.
• Enhanced accuracy: controlled fill-hold-rinse cycles reduce variability.
• Flexible solvent compatibility through interchangeable tubing types.
• Integration with temperature control for kinetic or thermal scanning studies.

Future Trends and Potential Applications

Advances in flow-based UV-Vis sampling may include:

• Deeper integration with laboratory information management systems for automated data logging.
• Expanded multiplexing beyond three channels through microfluidic manifolds.
• Miniaturized flow cells for reduced sample volume and waste.
• Smart sensor feedback for real-time viscosity and bubble detection.
• Extended compatibility with high-pressure or high-temperature applications.

Conclusion

The Cary Sipper accessory significantly enhances the efficiency, reproducibility and safety of UV-Vis spectroscopic analyses. By automating sample delivery and rinsing, laboratories can achieve up to 65 % time savings on routine assays, while maintaining precise control over measurement parameters.