摘要:
AN APPARATUS FOR BATCH ANALYSIS OF LIQUID SAMPLES WHEREIN SYRINGES ARE EMPLOED FOR DELIVERING REPEATABLE VOLUMES OF REAGENT TO A CELL PRIOR TO THE ADDITION OF A SAMPLE AND FOR WITHDRAWING LIQUID FROM THE CELLA AFTER ANALYSIS THEREOF. SENSING MEANS, SUCH AS A POLAROGRAPHIC OXYGEN SENSOR, IS MOUNTED IN THE SIDE WALL OF THE CELL WITH ITS SENSING CONTACTING THE LIQUID THEREIN. A STIRRING ELEMENT IS POSITIONED WITHIN THE CELL AND ROTATED ABOUT THE VERTICAL AXIS OF THE CELL SO THAT A HIGH TANGENTIAL STIRRING FORCE IS PRODUCED TO PROMOTE MIXING OF SAMPLE WITH REAGENT AND TO OPTIMIZE SENSOR PERFORMANCE, YET ONLY SMALL SAMPLE VOLUMES ARE REQUIRED. THE APPARATUS IS PARTICULARLY SUITED FOR RATE SENSING BATCH ANALYSIS OF BIOLOGICAL FLUIDS SUCH AS BLOOD OR URINE.
摘要:
A POLAROGRAPHIC SENSOR COMPRISING A PAIR OF ELECTRODES JOINED BY AN ELECTOLYTE WITH INNER AND OUTER MEMBRANES SEPARATING THE ELECTRODE AND ELECTROLYTE FROM THE SAMPLE MEDIUM. THE OUTER MEMBRANE IS PERMEABLE TO THE GAS BEING DETERMINED AND IMPERMEABLE TO ELECTROLYTE WHILE THE INNER MEMBRANE HAS AN OPENING THEREIN WHICH OVERLIES THE SENSING ELECTRODE OF THE SENSOR. THIS INNER MEMBRANE IS SUBSTANTIALLY LESS PERMEABLE TO THE GAS BEING ANALYZED THAN THE OUTER MEMBRANE AND IS HYDROPHILIC SO AS TO RETAIN A FILM OF ELECTROLYTE BETWEEN THE OUTER MEMBRANE AND THE ELECTRODES. PREFERABLY THE OUTER MEMBRANE IS FORMED OF POLYTETRAFLUOROETHYLENE AND THE INNER MEMBRANE OF POLYETHYLENE TEREPHTHALATE (MYLAR).