Determination of inorganic phosphate in drug formulations and biological fluids using a plant tissue electrode.

A suitable biosensor for the analysis of inorganic phosphate was developed by coupling the enzyme glucose oxidase to a slice of potato (Solanum tuberosum) containing the acid phosphatase, and using an amperometric Clark electrode as an indicating sensor. Phosphate concentration can be determined from its inhibition on the acid phosphatase activity. Measurements were carried out at steady-state conditions and the available concentration range of phosphate, repeatability and accuracy, on phosphate standard solutions, were experimentally determined. Finally the sensor was used in pharmaceutical and biological matrices. The results were compared with those ones obtained by Bartlett's spectrometric method.