Graphite tube cell assemblies for atomic absorption spectrometers

Abstract

Abstract A KNOWN TYPE OF HEATED SAMPLE CELL ASSEMBLY FOR ATOMIC ABSORPTION SPECTROSCOPY INCLUDES AN OPEN-ENDED GRAPHITE SAMPLE TUBE HAVING A CENTRAL HOLE FOR INITIALLY INTRODUCING THE SAMPLE INTO THE TUBE AND FOR ALLOWING AN INERT GAS TO CIRCULATE FROM THE OTHERWISE CLOSED HOUSING INTO THE TUBE TO PROTECT THE INTERIOR SURFACES FROM OXIDIZATION WHEN THE DEVICES IS HEATED, AS BY LARGE ELECTRICAL CURRENTS SUPPLIED FROM ELECTRODES IN CONTACT WITH BOTH ENDS OF THE GRAPHITE TUBE. THE PRESENT IMPROVEMENT INCLUDES THE ADDITION OF TWO FURTHER HOLES NEAR THE ENDS OF THE GRAPHITE TUBE TO REDUCE THE SPEED AT WHICH A GIVEN TOTAL PROTECTIVE GAS FLOW CAUSES THE SAME AMOUNT OF SAMPLE TO BE EXPELLED FROM THE OPEN END OF THE TUBE, THEREBY INCREASING USEFUL MEASURING TIME. PREFERABLY THE END HOLES ARE OFFSET SO AS TO CAUSE THE GAS FLOW ENTERING THE INTERIOR TO BE SUBSTANTIALLY TANGENTIAL TO THE INNER WALLS OF THE TUBE SO AS TO FORM A HELICAL OR CYCLONIC FLOW ALONG THESE WALLS, THEREBY MINIMIZING THE POSSIBILITY OF AMBIENT AIR FLOW REACHING THESE INNER WALL SURFACES. ADVANTAGEOUSLY, THE GRAPHITE TUBE MAY HAVE CONICALLY TAPERED ENDS, AND THE (ALSO GRAPHITE) ELECTRODES MAY BE ANNULAR AND INCLUDE COMPLEMENTARILY CONICALLY-SHAPED INNER SURFACES MATING WITH THESE CONICAL ENDS OF THE TUBE.

Inventors

• 👤 Klaus Braun
• 👤 Kurt Manthey
• 👤 Bernhard Welz

Bibliographic Details