High-Performance Paper-Based Fluidic Cassette for Mass Spectrometry Analyzing Caffeine and Nicotine Metabolites

This paper develops a high-performance paper-based fluidic cassette for mass spectrometry (MS) analyzing caffeine and nicotine metabolism in urine and hair samples. The device uses a novel two-dimensional paper chromatography to separate the species in the liquid sample and then analyze the metabolic species via the MS using a specially designed paper spray ionization (PSI) mechanism. The paper-based fluidic chip is produced in the laboratory filter paper with the IR laser for patterning the multifunctional paper for sample chromatography and multiple tip for PSI. To enhance the MS detection performance, an integrated sliding cassette with a pair of pinching electrodes is designed for retarding electrospray at the neighboring tooth and simultaneously focusing the main spray plumb for sample ionization. Numerical and experimental results show that the undesired neighboring electrospray plumbs are significantly retarded by the applying electric field at the pinch electrodes. Successfully detecting the caffeine species in the urine sample and the nicotine/cotinine species in the extracted solution of a heavy smoker's hair are demonstrated with the developed device. The developed paper fluidic cassette has shown its potential in the application of drug abuse prevention.