Towards a Quantitative Colorimetric Gold Nanoparticle-Based Assay for Measuring ppm and Sub-ppm Aqueous Nitrite Levels

Abstract

Prior publications and work from our group have demonstrated a colorimetric assay coupling the Griess reaction with gold nanoparticle aggregation to detect the concentration of nitrites. However, a major disadvantage of this assay is it is slow and needs to be conducted at 95oC. This project takes a closer look at the mechanism of aggregation and lower the reaction temperature. The modifications allow the colorimetric measurement of nitrite concentrations exceeding 230 M (10 ppm) at room temperature, greater than 3 M (130 ppb) at 50oC, and potentially as low as about 0.05 M (2 ppb) at 95oC. This work sets the foundation for the development of an accurate, precise, inexpensive and portable nitrite measurement kit.