Abstract: An electrochemical sensor with a gelled membrane for prolonging the useful life of an ion-selective electrode. The gelled membrane is a hydrophilic membrane having a specially-formulated gel layer coated on one side. The gel-coated side of the gelled membrane is in intimate contact with the ion-selective membrane and separates the ion-selective membrane from the test samples and the calibration and cleaning fluids. The gelled membrane is a semi-permeable barrier which allows passage of the species to be measured while inhibiting the passage of surfactant and proteinaceous material into the polymeric ion-selective membrane.

Abstract: The position calculation system has position and energy calculators for each scintillation event. After correcting the position and energy values using tables, non-uniform random distribution variance values are added to the position and energy values with the variance added being a product of the random number and a constant precalibrated for the given position. The variance injected position and energy values have a more uniform resolution and substantially remove artifact characteristics in the scintillation camera's image.