Philippine Journal of Science
149 (3-a): 711-717, October 2020
ISSN 0031 – 7683
Date Received: 19 Feb 2020

 

Digital Image Photometric Analysis of Nickel(II) in Alkaline Solution with Dithizone as Complexing Agent Using a Mobile Phone Camera

 

Angelica C. Pagala, Cherry Mae T. Ravidas, Jennifer Q. Pillas,
and Ernesto J. del Rosario*

 

Institute of Chemistry, College of Arts and Sciences University of the Philippines Los Baños, College, Laguna 4031 Philippines

 

*Corresponding author: ejdros@yahoo.com

 

[Download]
Pagala A et al. 2020. Digital Image Photometric Analysis of Nickel(II) in Alkaline Solution with Dithizone as Complexing Agent Using a Mobile Phone Camera. Philipp J Sci 149(3A): 711–717. https://doi.org/10.56899/149.3A.03

 

ABSTRACT

Quantitative analysis of nickel(II) in aqueous alkaline solution, with dithizone as a complexing agent, was done using digital image photometry (DIP) and the results were compared with those using conventional visible spectrophotometry (VS). Digital color photographs of prepared standard and sample solutions of Ni(II) were taken using a fabricated lightbox with a 24-well sample holder and iPhone 5S mobile phone camera. RGB values were determined from the photographs using ImageJ software and plots of Red value, L*, a*, and b* as DIP parameters were constructed in order to calculate Ni(II) concentrations. No significant differences in Ni(II) concentrations were observed at a 95% confidence level based on DIP and VS. Performance criteria were set and various tests were conducted for the limit of detection (LOD), limit of quantification (LOQ), linearity/working range, repeatability, and selectivity. The DIP results satisfied the minimal requirements in terms of method validation criteria according to published guidelines. Among the DIP parameters, b* gave results with the highest linearity and accuracy based on the coefficient of determination (R2), as well as plots of least significant differences (LSDs) and linear regression residuals. The results of the present study show that DIP, which uses a relatively inexpensive mobile phone camera, is a promising alternative to the conventional method using an expensive spectrophotometer.