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UV-VIS Spectrometer

Overview

Thumbnail image of UV-VIS Spectrometer UV-vis spectroscopy is the measurement of how much light is absorbed by a sample at a specific wavelength to determine the concentration of a compound in that sample through Beer’s law. Samples are mixed with other reagents to develop a color complex which is then measured for absorbance at a wavelength that is known to absorb that compound's color complex.

Instrument Make and Model

Agilent Cary 100 UV-Vis Spectrophotometer

Estimated Measurement Time

  • Sample Preparation: up to 7 hours
  • Sample Measurement: 1–2 mins/sample

Quantity of Sample Material

0.5–3 mL per sample; dependent number of color chemistries and dilution

Principles & Analytical Capabilities

The Agilent Cary 100 UV-Vis Spectrophotometer can measure wavelengths in the range of 190–900 nm with a working range up to 4.0 Abs. Linearity over that range will be dependent on the method used as some may only have a linear response up to a certain concentration or absorbance. Samples that fall outside of the primary linear range will require dilution to ensure all samples fall within the same linear range. Absorbances of standards will be plotted against concentration to create a calibration curve to then calculate the concentrations of samples.

Data Generated

Data components:

  • NH4
  • NO2
  • NO3
  • HPO4
  • H4SiO4

Data files:

  • Tabular data (CSV): tabular file of absorbance values of all standards and samples measured.
  • Calibration file (XLSM): workbook containing calibration and processed spectrophotometric results.

Data Example

Graph of Ammonium and phosphate concentrations from Hole U1609A of IODP Expedition 401 on the continental slope of the Portuguese margin.
Ammonium and phosphate concentrations from Hole U1609A of IODP Expedition 401 on the continental slope of the Portuguese margin.1

Procedures & Manuals

References

1  Flecker, R., Ducassou, E., Williams, T., Amarathunga, U., Balestra, B., Berke, M. A., Blättler, C. L., Chin, S., Das, M., Egawa, K., Fabregas, N., Feakins, S. J., George, S. C., Hernández-Molina, F. J., Krijgsman, W., Li, Z., Liu, J., Noto, D., Raad, F., … Yousfi, M. Z. (2025). IODP Expedition 401 Spectrophotometry [Data set]. International Ocean Discovery Program. https://doi.org/10.5281/zenodo.16459629