Extraction Membranes for Non-Invasive Monitoring of Biological Fluids

A small device that could reliably measure ammonia in biological fluids would have a myriad of clinical applications. Diagnosis and management of disorders that impact absolute or relative changes in renal excretion of ammonia would be greatly aided by such a device. These include conditions that alter systemic acid/base homeostasis, metabolic conditions, and diseases of the kidney and liver. However, traditional practical and technical limitations of urine ammonia measurement have impeded its use as a routinely employed biomarker in medicine. We are developing a membrane for extracting aqueous ammonium in urine and converting it to gaseous ammonia for detection with a colorimetric gas sensor. We have modified membranes to create an ammonium/ammonia extraction membrane. We will present our results on testing membranes with model ammonium chloride solutions and our colorimetric indicator.