All-solid-state miniaturized fluorescence sensor array for the determination of critical gases and electrolytes in blood.

We describe a six-channel, all-solid-state, miniaturized fluorescence sensor array for the precise determination of blood analytes for medical diagnostic purposes. The device features superblue LEDs as light sources, GRIN optics, and photodiodes, assembled according to pigtailing procedures (Bruno, A. E.; et al. Trends Anal. Chem. 1994, 13, 190−198). The numerical aperture of the fluorescence optics is 0.46, rendering a collection efficiency of 2.4%. The performance of this instrument has been evaluated in terms of dynamic response, linearity, channel reproducibility, reversibility, long-term drifts, photobleaching of indicator, cross-talk, ionic strength, and selectivity in pH measurements. The responses of the pH sensing membranes were optimized in the physiological range. Responses are linear with typical values of ∼1.5 V/pH unit, with limits of decision of 24 mV, which corresponds to pH resolutions of 0.03 pH unit. Under continuous illumination, using calibration buffers, the sensors display nonstatis...