Maria Katrina P. Acuros (February 2009)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Salinity of water is essential for the growth of marine organisms, thus accuracy of salinity should be taken seriously. By comparing the most common methods used in measuring water salinity, the most reliable one was determined.
This study investigated the accuracy and reliability of Refractometer, Fajan’s Titration and Gravimetric Chloride Determination in determining the salinity of aqueous NaCl solution of various concentrations (10 ppt, 33 ppt, 40 ppt) maintained at the three temperature levels (5°C, 17°C, 38°C). After making the research design and preparing the salt solution that was used, salinity was measured using a Refractometer, Fajan’s Titration and Gravimetric Chloride Determination. Accuracy of the Methods was then compared.
The mean salinity was measured by the Refractometer, Fajan’s Titration and Gravimetric Chloride Determination were relatively comparable with each other for all the pairings of concentration except for the 10 ppt- 17°C solution where refractometer showed a very large variation. However, one-sample t test showed that there is no significant difference in the mean salinity for all the pairings of concentration measured by the Refractometer, Fajan’s Titration against GCD.
The results of this study showed that salinity value measured by the refractometer and Fajan’s titration showed a high degree of conformity to the value measured using the GCD.