A POCKETSIZE DEVICE TO MEASURE ARSENIC IN WATER
Walter Kosmus, Ph.D., University of Graz
Since a decade we know about the dramatic situation in West Bengal. Only few years ago we
learned that the situation in Bangladesh is worst and many arsenic-affected areas in other parts of
the world have been detected recently. Undoubtedly new areas are yet to be discovered. From the
scenario already known we have realized that the arsenic content in the drinking water sources
shows a characteristic high degree of spatial variability. Therefore it is necessary to analyse each
tube well one by one. This means simply for Bangladesh to analyze more than 5 millions of
samples. In the most affected countries the lack of modern analytical facilities makes it
impossible to accomplish this task by laboratories. The lack of an appropriate logistics for the
whole analytical process, sampling, transportation of the samples to the laboratories and
elucidation of the results magnifies this problem. The analysis right in the field directly at the
spot could help to solve the problem. With the experience based on our Arsenator 510 we have
continued our efforts to design an applicable device. Now we have accomplished a small
instrument which fits in a pocket. With this device we can quantify the intensity of the
yellow-brownish spot on the reagent-paper, which results from the well known Gutzeit reaction.
While for the human eye the yellow spot is hard to evaluate, it is easy for an optical tool at the
right wave lenght. The basic technical data are: Detection limit: 5 mg/L for a sample volume of
100 mL Analytical range: 5 to 120 mg/L, higher concentrations require a smaller sample volume
Resolution: the result is given in steps of 5 mg/L Precision: +/- 2 mg/L, but the result is rounded
to the next n x 5 mg/L Only solid chemicals are used to generate the arsine gas. This has a major
advantage for the analysis in the field compared to the use of zinc and acid.
CORRESPONDING AUTHOR: Walter Kosmus, Ph.D., Institute of Chemistry, Karl-Franzens
University of Graz, Universitaetsplatz 1, A-8010 Graz, Austria