Optimization and validation of a differential pulse anodic stripping voltam-metric (DPASV) method for trace analysis of inorganic arsenic in contaminated water
2018
Magalona, M.L. | Peralta, M.M. | Lacsamana, M.S. | Sabularse, V.C. | de Guzaman, C.C.
The maximum contamination limit set by the U.S. Environmental Protection Agency (EPA) for arsenic in drinking water is 10 ppb in view of the adverse effects of chronic arsenic exposure on human health. Hence, there is a need to develop an inexpensive, field-operable method that can quantify arsenic at or below this concentration to ensure compliance with EPA regulations without exposure of the analyst to toxic arsine gas. An electroanalytical method was optimized and validated to analyze trace inorganic arsenic as As(III) and total As (As(III) + As(V)) using differential pulse anodic stripping voltammetry with a gold disk as the working electrode, Pt/Ti rod as the auxiliary electrode, and Ag/AgCl as the reference electrode. The study was conducted at the Institute of Chemistry, University of the Philippines Los Baños [Philippines] from June 2015 to October 2016. The electroanalytical method was found to be precise and sensitive based on the resulting RSD values ( 13%). It also had a satisfactory percent recovery of 91% for As(III) and 81% for As(V). The limit of detection of As(III) and As(V) were 2.24 and 6.96 ppb, respectively while the limit of quantification of As(III) and As(V) were 7.49 and 23.19 ppb, respectively. The total arsenic content of groundwater samples obtained by this method was validated with inductively coupled plasma optical emission spectrophotometry, and statistical analysis using the t-test showed that the two methods were not significantly different. This in expensive and rapid method allows for speciation of the arsenic species found in field water samples and will be a great boon for monitoring water quality for farming communities that rely on raw groundwater for cooking and drinking.
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