Comparison of spectrophotometric and digital photometric methods for the determination of total phosphorus content in river water

Date

4-2011

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Kaligayahan, Joy Elaine P.

Co-adviser

Del Rosario, Ernesto J.

Committee Member

Fajardo, Norma N.

Abstract

Total phosphorus concentrations of river water from Talisay River, Bataan were quantified using spectrophotometry and digital photometry. Spectrophotometry was performed to validate the results of the digital photometric method. The digital photometric method utilised a digital camera, a light box, RGB Analysis of Image Colors software, and a computer. Three equations were used for the determination namely percent luminance equation, a* (red-green component) equation, and b* (yellow-blue component) equation. Ascorbic acid method for the determination of total phosphorus content was used for the experiment. The method utilised the reaction of ammonium molybdate and potassium antimonyl tartrate in acidic medium with orthophosphate to form phosphomolybdic acid which is reduced to molybdenum blue by ascorbic acid, read at 880 nm. The mean concentrations of phosphorus obtained using spectrophotometry are: 0.421±0.029 ppm (Site 1); 0.393±0.015 ppm (Site 2); 0.414±0.005 ppm (Site 3); 0.407±0.005 ppm (Site 4); and 0.409±0.022 ppm (Site 5). The mean concentrations of phosphorus obtained using digital photometry are: 0.500±0.129 (Site 1); 0.451±0.031 ppm (Site 2); 0.513±0.065 (Site 3); 0.467±0.014 (Site 4); and 0.455±0.085 (Site 5). Assessment of the accuracy, precision and repeatability, of the digital photometric method in comparison with spectrophotometry, the standard method, showed that the digital photometric method can be repeatable, accurate and precise. Mean total phosphorus concentration obtained from the samples ranged from 0.104-0.547 ppm. Analyzed river water from the Talisay River did not exceed the maximum total phosphorus standard of 1.00 ppm set by the Department of Environment and Natural Resources for Class C water.

Language

English

Location

UPLB Main Library Special Collections Section

Call Number

LG 993.5 2012 C42 A78

Document Type

Thesis

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