Pressure stepped microwave assisted digestion

摘要

An instrument and method for high pressure microwave assisted chemistry are disclosed. The method includes the steps of applying microwave radiation to a sample in a sealed vessel while measuring the temperature of the sample and measuring the pressure generated inside the vessel and until the measured pressure reaches a designated set point, opening the vessel to release gases until the pressure inside the vessel reaches a lower designated set point, closing the vessel, and repeating the steps of opening the vessel at designated pressure set points and closing the vessel at designated pressure set points to the sample until the sample reaction reaches a designated high temperature. The designated set points can controllably differ from one another as the reaction proceeds. Microwave energy can be applied continuously or intermittently during the opening and closing steps. The apparatus includes a microwave cavity, a microwave transparent pressure resistant reaction vessel in the cavity, a cap on the reaction vessel, a pressure sensor for measuring pressure in the vessel, a temperature sensor, and means for opening and closing the cap at predetermined pressure set points measured by the pressure sensor to release pressure from the vessel.

主权项

1. An apparatus for microwave assisted high pressure high temperature chemistry comprising:
a microwave cavity: a microwave-transparent pressure-resistant reaction vessel resistant to chemical attack in said cavity; a cap on said reaction vessel; a pressure sensor for measuring gas pressure applied against said cap from within said vessel; a block that bears against said cap; and a horizontally reciprocating arm connected to said block for raising and lowering said block to open and close said cap at stepwise periodic different predetermined pressure set points measured by said pressure sensor to release pressure from said vessel.