Chemical sensing using an integrated microfluidic system based on the Berthelot reaction

The Berthelot reaction is a well-established colorimetric method for the de termination of ammonia. It has been investigated with the particular aim of incorporating it into a simple, reliable analytical microfluidic sensing s ystem. Absorbance measurements for the complex formed when this reaction is performed in microfluidic chips compare very well to those obtained in a s pectrophotometric system. The very high reproducibility and efficiency of m ixing by diffusion in the microfluidic chip make it a useful tool for futur e studies of other chemical methods where kinetics are a limiting factor fo r the response time. (C) 2001 Elsevier Science B.V. All rights reserved.