Comparison spectrophotometric and digital photometric and digital photometric determination of total phenolics in Sargassum sp. and Gelidiella acerosa

Date

4-2012

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ernesto J Del Rosario

Abstract

SINAD, KORINA VIDA G. Institute of Chemistry, College of Arts and Sciences. University of the Philippines Los Banos, April 2012. Comparison of Spectrophotometric and Digital Photometric Determination of Total Phenolics in Sargassum sp. and Gelidiella acerosa.

Adviser: Dr. Ernesto J. del Rosario

Advisory Committee: Prof. Joy Elaine Kaligayahan Prof. Kristel Mae Rabanzo

The content of total phenolics in aqueous extracts of Sargassum sp. and Gelidiella acerosa was determined by visible spectrophotometry and digital photometry using the Folin-Ciocalteau assay. The total phenolics content (in ppm) for the dry samples of Sargassum sp. was 40.88 ± 0.95 using spectrophotometry; corresponding results using digital photometry were 36.82 ± 2.95, 39.49 ± 1.10 and 44.38 ± 1.96 ppm based on % luminance, b* plot and a* plot, respectively. For Gelidiella acerosa, the total phenolics content (in ppm) was 1.89 ± 0.28 using spectrophotometry; corresponding results using digital photometry were 2.37 ± 0.20, 1.87 ± 0.29 and 16.6 ± 0.74 based on % luminance, b* plot and a* plot, respectively. The spectrophotometric and digital photometric results were not significantly different at 95% confidence level except when using the a* plot. The experiment was repeated with a new set of standard and sample solutions. The t-test showed that the first and second experiments were comparable at 95% confidence level. Validation of accuracy using both photometric methods using known concentrations of KMnO4 gave results that were comparable with the known concentration at 95% confidence level. The results of this study showed that digital photometry can serve as an alternate for spectrophotometric analysis of total phenolics in macroalgal samples as it provides comparable, accurate and repeatable results.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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