Evaluation of arsenic field test kits for drinking water analysis

Seven arsenic field test kits were evaluated for their ability to detect arsenic III, V, and a combination of species, and their performance was compared with that of graphite furnace atomic absorption spectrophotometry. Performance was evaluated for precision, accuracy, matrix effects, linearity, operator bias, and ease of use. Precision, determined by standard deviation, was relatively good for all test kits. However, accuracy, as calculated using percent recoveries, varied greatly among the test kits. Matrix effects were evaluated using known additions of sulfide and antimony in reagent water. Field samples were also tested at various arsenic concentrations to determine performance throughout the working range (linearity) of the test kits. Results indicated that two of the seven field test kits met acceptable criteria of accuracy, precision, linearity, expense, and ease of use as defined by the authors. Given the varied performance among the testing kits, the authors concluded that water professionals should be cautious in choosing field test kits for noncompliance analyses.