NC State
Kong, F., and Ni, Y. (2009). "Development of cellulosic paper-based test strips for Cr(VI) determination," BioRes. 4(3), 1088-1097.


Paper-based test strips specific for the Cr(VI) determination in aqueous solutions were developed by impregnating a color-forming reagent, diphenylcarbazide, and a quaternary ammonium salt (Aliquat 336) into paper sheets. The results showed that the quaternary ammonium salt could effectively retain the colored complex in the paper substrate. This paper-based test strip showed a high selectivity for Cr(VI) in the samples to be tested. The method was applied to synthetic samples, and the results were compared to these from a reference method. The current work demonstrated that with a color chart, this portable paper-based test strip has the potential to be used for field screening or on-site semi-quantitative analysis.
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