Instrumentation Laboratory

Edward C Eldred

Stanley B Smith, Jr

Robert G Schleicher

Method and apparatus for automatically depositing predetermined reproducible amounts of nebulized samples into a furnace atomizer of an atomic absorption spectrophotometer, the atomizer being provided with an aperture, wherein a plurality of sample containers containing samples to be analyzed are arranged and successively transported on a sample supporting device, with the sample containers being open at their upper ends. The samples are aspirated from the containers via a suitable means and into a nebulizer-mixing chamber device wherein they are nebulized and mixed until such time that the nebulized sample achieves full equilibrium therein. A means is provided for depositing the nebulized and now equilibrated sample from the chamber device through the aperture into the furnace atomizer. The deposition of predetermined and reproducible amounts of nebulized samples is controlled by a means which, in a preferred embodiment, comprises a vacuum source in valved communication with the means for depositing the nebulized sample in a way that aerosol deposition is effected only during the time period when the vacuum source is shut off from the means for depositing the aerosol sample by shutting off the valve. In another preferred embodiment, the means for controlling the amount of aerosol sample being deposited comprises a fluidic switch in communication with the nebulizer-mixing chamber device on the one hand and with the means for depositing the sample on the other. Hence, sample deposition takes place only during the time period when such communication from the chamber device to the deposition means is effected by the fluidic switch.

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Wenham, MA, United States of America

Edward C Eldred