Microwave heated digesting system for digesting materials to be analyzed

Abstract

A continuous flow microwave heated digesting system, which is especially useful for digesting samples of materials to be analyzed with an atomic absorption spectrometer (ASS), includes a chamber, a source of microwave radiation into the chamber, thin bore chemical resistant an microwave transmissive tubing within the chamber onto which the microwave radiation impinges to heat contents of the tubing, and a pump or other suitable apparatus or device for passing through the tubing the sample of material to be digested, dispersed in a digesting medium for it, which sample in the digesting medium is in the form of a discrete slug in a carrier liquid. A suitable device is provided for inserting into the carrier liquid, which is usually water, the slug of material to be digested in the digesting liquid and a backpressure controller is also provided to control backpressure on the slug and the carrier liquid n the tubing. By such backpressure control the slug develops bubbles during the time it is being heated and condenses to liquid form upon cooling thereafter. The bubbling action aids digestion of the material to be digested but the bubbles ought to be condensed before analysis of the digested material by an AAS or other analytical apparatus. Such condensation is effected by a cooling apparatus and the digested material in the digesting liquid in the carrier is filtered by a special filter before being analyzed, which protects the backpressure controller and the AAS and improves AAS analytical results.