A1787 Optimization of arsenic analytical methodologies in urine by HG-AAS for routine determinations in Uruguayan workers

Thursday, March 22, 2012
Ground Floor (Cancun Center)
Nelly Mañay, Toxicology and Environmental Hygiene, University Of The Republic, Montevideo, Uruguay
Cristina Alvarez, Toxicology and Environmental Hygiene-DEC, Faculty Of Chemistry - University Of The Republic (udelar), Montevideo, Uruguay
Mariela Piston, Analytical Chemistry Department, Faculty Of Chemistry - University of The Republic (Udelar), Montevideo, Uruguay
Giovanna. Clavijo, Toxicology and Environmental Hygiene, Faculty of Chemistry - University of The Republic (Udelar), Montevideo, Uruguay
Maria Elvira Gomez, Toxicology and Environmental Hygiene, Faculty of Chemistry - University of The Republic (Udelar), Montevideo, Uruguay
Introduction
Arsenic (As) exposure occurs as a result of inhalation of dusts and fumes at the workplace and/or ingestion of arsenic contaminated water and food. In Uruguay, As exposure at the workplace is been taken into account to systematically assess worker’s health risks as new occupational legal regulations have been recently established by the Ministry of Public Health. As a consequence, there is a special need of developing feasible analytical tools locally, to assess worker’s urine As levels and its speciation to law-abiding.

Methods
The determination of low arsenic concentrations requires highly sensitive techniques and no ICP-MS is available in this country, so a simple method for routine determinations of total and inorganic arsenic in urine is proposed and validated. It is based on a commercial flow system with detection by Hydride Generation (Varian VGA77) - Atomic Absorption Spectrometry (Varian SpectraAA 55B). The sample treatment for total As was optimized for urine using sulfuric acid and potassium persulfate for the elimination of organic matter, and potassium iodide and hydrochloric acid for the reduction of As(V) to As(III). For inorganic As determination, only the reduction step was carried out.

Results
Detection and quantification limits were 0.26 µgL-1, linear range was up to 10 µgL-1. Accuracy was evaluated by spiking various urine samples, with recoveries in the range 90-110%. Precision (repeatability, RSD%) was better than 10% for urine samples

Discussion
Arsenic in urine recommended limits are less than 35 µgL-1 on occupational exposed workers (ACGIH-BEI®) and 10-20 µgL-1 on general population. These levels are considered as reference in Uruguay, so the figures of merit of the methodology (HG-AAS), are appropriate for routine monitoring of total and inorganic As in urine, according to international recommendations and Uruguayan regulations. Currently, biomonitoring of inorganic arsenic in urine from workers exposed to CCA wood preservative is being performed by this team.

See more of: Biomonitoring of Chemical exposures experiences in Developing countries
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