Optoelectronic detectors and flow analysis systems for determination of dialysate urea nitrogen

Three compact flow analysis systems based on flow-through optoelectronic devices and microsolenoid pumps and valves dedicated for determination of urea in effluent liquid produced by artificial kidney in the course of hemodialysis treatments have been developed. The developed photometric devices operate according to paired detector diode principle. For the first flow analysis system an optoelectronic urea biosensor based on pH-sensitive film enzymatically modified with urease has been applied. In the second system open-tubular urease biosensor and optical detector of ammonia by Berthelot reaction have been used. The third non-enzymatic analytical system is based on optoelectronic detector of the product formed in reaction of urea with modified Ehrlich reagent. The analytical utility of developed flow analysis systems has been tested with real samples of spent dialysate. The results of dialysate urea nitrogen determination are comparable with those obtained using reference off-line method recommended for clinical analysis. Advantages and drawbacks of developed prototypes have been compared and discussed. (C) 2015 Elsevier B.V. All rights reserved.