REDUCED PRESSURE LIQUID SAMPLING
Processing a liquid sample ( 204 ) having an analyte ( 206 ) by reducing a pressure in a container ( 200 ) including the liquid sample to less than atmospheric pressure and maintaining a reduced pressure in the container. Reducing the pressure in the container ( 200 ) and optionally agitating the liquid sample increases an amount of vapor-phase analyte ( 206 ) above the liquid sample. In some cases, a concentration of the vapor-phase analyte is further increased, for example, with a chemical trap ( 502 ). The vapor-phase analyte can be provided to a chemical analyzer ( 302 ).
1 . A method of processing a liquid sample comprising an analyte, the method comprising:
reducing a pressure in a container comprising the liquid sample to less than atmospheric pressure;
wherein reducing the pressure in the container increases an amount of vapor-phase analyte above the liquid sample.
2 . The method of claim 1 , further comprising agitating the liquid sample while maintaining a reduced pressure in the container.
3 . The method of claim 2 , wherein agitating the liquid sample comprises aerating the liquid sample using one or more of a pulsed valve, a leak valve, and a vacuum regulator.
4 . The method of claim 3 , wherein agitating the liquid sample further comprises exciting the liquid sample with an ultrasonic transducer to increase the agitation efficiency.
5 . The method of claim 4 , further comprising sealing the container such that the container is air-tight.
6 . The method of claim 5 , wherein reducing the pressure comprises reducing the pressure to a pressure above that at which the liquid sample boils.
7 . The method of any claim 6 , further comprising removing some of the vapor-phase analyte from above the liquid sample, and increasing a concentration of the vapor-phase analyte removed from above the liquid sample relative to a concentration of the vapor-phase analyte above the liquid sample.
8 . The method of claim 7 , wherein increasing the concentration of the vapor-phase analyte removed from above the liquid sample relative to the concentration of the vapor-phase analyte above the liquid sample comprises concentrating the vapor-phase analyte removed from above the liquid sample using a chemical trap, and releasing the vapor-phase analyte from the chemical trap to a chemical analyzer.
9 . The method of claim 8 , further comprising reducing a pressure in the chemical trap before releasing the vapor-phase analyte to the chemical analyzer.
10 . The method of claim 9 , wherein the chemical analyzer comprises a mass spectrometer.
11 . A liquid sample processing system comprising:
a container; and
a vacuum apparatus coupled to the container;
wherein the liquid sampling processing system is configured to increase an amount of vapor-phase analyte above a liquid sample in the container by reducing a pressure in the container to less than atmospheric pressure.
12 . The liquid sample processing system of claim 11 , further comprising an agitating apparatus coupled to the container.
13 . The liquid sampling processing system of claim 12 , wherein the container comprises an inlet port and an outlet port.
14 . The liquid sample processing system of claim 13 , further comprising a pressure monitoring apparatus coupled to the container.
15 . The liquid sample processing system of claim 14 , further comprising a pressure control apparatus coupled to the container.
16 . The liquid sample processing system of claim 15 , wherein the agitating apparatus comprises a sparging apparatus.
17 . The liquid sample processing system of claim 16 , wherein the sparging apparatus comprises one or more of a pulsed valve, a leak valve, and a vacuum regulator.
18 . The liquid sample processing system of claim 17 , wherein the agitating apparatus further comprises an ultrasonic agitator to increase the agitation efficiency.
19 . The liquid sample processing system of claim 18 , further comprising a chemical trap coupled to the container.
20 . The liquid sample processing system of claim 19 , wherein the chemical trap is a pre-concentrator.
21 . The liquid sample processing system of claim 20 , further comprising a chemical analyzer coupled to one or more of the container, the chemical trap, and the vacuum apparatus.
22 . The liquid sample processing system of claim 21 , wherein the chemical analyzer comprises a mass spectrometer.