Quantitation of Nucleic Acids – Trace Measurement Using TrayCell and Nano Stick –

Importance of Topic

Ultraviolet-visible spectrophotometry plays a central role in modern analytical chemistry, enabling rapid and reliable quantitation of biomolecules such as nucleic acids at trace levels. Advances in microvolume sampling tools like TrayCell and Nano Stick expand the capabilities of conventional UV-VIS spectrophotometers, allowing researchers to work with minimal sample amounts and maintain high accuracy and precision, critical for fields ranging from molecular biology to quality control.

Objectives and Study Overview

This study demonstrates how the Shimadzu UV-1900 spectrophotometer, combined with two microvolume accessories—TrayCell and Nano Stick—can accurately quantify lambda-DNA at concentrations down to tens of nanograms per microliter. The aim was to establish calibration curves, assess measurement repeatability, and compare performance of both sampling devices under identical conditions.

Methodology and Instrumentation

Calibration series of lambda-DNA standards and an unknown sample (prepared by ethanol precipitation) were measured at 260 nm and background corrected at 320 nm over a wavelength range of 220 to 330 nm. Key parameters included low scan speed and 1 nm sampling pitch.

Used Instrumentation

• Shimadzu UV-1900 UV-VIS spectrophotometer
• TrayCell microvolume cell (1.0 mm path length, 4 μL sample)
• Nano Stick microvolume cell (0.5 mm path length, 3 μL sample)

Main Results and Discussion

TrayCell measurements produced a calibration curve with slope 0.0021 Abs per concentration unit and R2 of 0.9999. Unknown sample concentrations were 373 ng/μL (diluted) and 1020 ng/μL (undiluted). Ten replicates at 440 ng/μL yielded a coefficient of variation (CV) of 0.41% at 260 nm. Nano Stick results showed a slope of 0.0010 Abs per concentration unit with R2 of 0.9999; unknown sample values were 365 ng/μL (diluted) and 1066 ng/μL (undiluted). Ten replicates at 440 ng/μL gave a CV of 0.47%. Both devices demonstrated excellent linearity and repeatability with microvolume samples.

Benefits and Practical Applications

• Accurate quantitation of nucleic acids using minimal sample volume
• Rapid purity assessment via absorbance ratios
• Versatile Biomethod Mode for multiple bioassays (Lowry, BCA, Bradford, Biuret, UV)
• Space-saving design and intuitive touchscreen UI

Future Trends and Opportunities

Ongoing developments may include further miniaturization of optical cells, integration with automated sample handling and microfluidic platforms, expansion of built-in bioassay protocols, and enhanced data connectivity for cloud-based analytics. Such innovations will drive higher throughput and broader adoption in research and quality control environments.

Conclusion

The combination of the Shimadzu UV-1900 spectrophotometer with TrayCell or Nano Stick provides a robust solution for trace-level nucleic acid quantitation. Exceptional linearity, precision, and ease of use make this approach well suited for laboratories requiring reliable results from limited sample volumes.

Reference

Shimadzu Corporation. Application Note LAAN-A-UV-E072 – Quantitation of Nucleic Acids Using TrayCell and Nano Stick. First Edition, May 2018.