Microwave heated digesting system.

摘要

A continuous flow microwave heated digesting system includes a source of microwave radiation into a chamber (23), thin walled chemical resistant and microwave transmissive tubing within such chamber onto which the microwave radiation impinges to heat contents thereof, and means for passing through such thin walled tubing material to be digested in a digesting medium therefor, so that the material is digested. It has been found that for quick and effective digestions the tubing will often be of an internal diameter in the range of 0.5 to 1 mm. and will be heated for a length in the range of 5 to 50 meters, so the heating time of a sample to be digested will be at least five seconds and normally will be less than 3 minutes, during which time such digestion will be essentially completed. Means are provided for inserting into a stream of carrier liquid, such as water, a slug, such as a 1 ml. slug, of sample in digesting liquid (acid), which is passed through the tubing (which is coiled inside a microwave chamber), and after completion of digestion is cooled (27) and is passed directly to an atomic absorption spectrometer (43), where its spectrum is recorded and the analysis of the sample is reported. The slug of sample in acid may be added to the system via an injection valve and loop by means of syringe injection (49) or other suitable charging means. Backpressure will be maintained (41) on the system and filtration (35) of any undigested solids will very preferably be effected to prevent any possible blockages of the system.