Method validation for analysis of arsenic in water samples using leuco-malachite green, rhodamine B, and iodimetric method

Date

10-2013

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Josefina L. Solivas

Restrictions

Restricted: Not available to the general public. Access is available only after consultation with author/thesis adviser and only to those bound by the confidentiality agreement.

Abstract

The methods, iodimetry and two spectrophotometric methods using rhodamine B and leuco-malachite green as chromophoric agents were evaluated and validated for their use in the analysis of arsenic in water samples. The iodimetry is commonly used in the standardization procedure of arsenic standards. The limit of quantitation (LOQ) and limit of linearity (LOL) of the procedure were determined to be 0.312 μg/mL and 2.0 μg/mL, respectively. The limit of detection (LOD) is 0.103 μg/mL. The two spectrophotometric methods using rhodamine B and leuco-malachite green dye were tested with and without iodate. For rhodamine B procedure without iodate, the LOQ was determined to be 222.5 μg/mL, the LOD was 73.4 μg/mL, and the LOL was at 500 μg/mL. While for the rhodamine B procedure without iodate 0.297 μg/mL, LOQ 0.0979 μg/mL, LOD and 2.00 μg/mL, LOL were determined. Iodate was added to react with the analyte as excess unreacted iodate then reacts with the dye same with that of the leuco-malachite green. The leuco-malachite green method?s LOQ, LOD, and LOL were 0.207 μg/mL, 0.0683 μg/mL, and 0.500 μg/mL, respectively. The three methods can analyze samples with μg/mL levels of analyte but not trace (μg /L) concentrations. The concentration of arsenic (III) in the water samples (paddy soil extract, deep well water (unchlorinated, free-flowing and chlorinated, pumped), Molawin creek water (higher elevation, flat rocks and lower elevation, near CEAT sewer), and Physical Science Building (Wing A) tap water) used in this study using differential pulse cathodic stripping voltammetry (DPCSV) were in the range of <0.30 ? 7.79μg/L (Franco, 2013). The methods studied were not suited for analysis of these natural water samples but may be useful in the analysis of waste water contaminated by arsenic, mine tailings, and arsenic containing laboratory waste.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2013 A13 /P33

Document Type

Thesis

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