Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
  • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
  • B01L3/505—Flexible containers without fluid transport within
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/10—Devices for withdrawing samples in the liquid or fluent state

Definitions

• the invention relates to a method of sampling a liquid containing a dissolved gas or other volatile substances or components, especially water with dissolved radon, which liquid during the sampling is to be collected in a container substantially without contact arising between the liquid and a surrounding atmosphere.
• the invention also relates to a device for use with the method.
• the object of the analysis is a gas dissolved in a liquid or liberates gas which are soluble in a li ⁇ uid
• the sampling- or collecting of the liquid can take place without it getting into contact with the surrounding atmosphere.
• a gas dissolved in the liquid would when the liquid is exposed to the surrounding atmosphere, escape thereto, especially when the liquid is naturally absent from the surrounding atmosphere or only present therein such that its partial pressure is substantially lower than its partial pressure when dissolved in the li ⁇ uid.
• the object of the analysis is a quantitative determination of the gas dissolved in the liquid, said circumstance may thus lead to that such an analysis cannot be carried out or gives highly errounous results. Especially is this case in the determination and analysis of radon dissolved in water.
• Radon is generated from natural occurences of radioactive elements in the earth's crust and is, as it is solutable in water, disposed to accumulate in the ground water in dissolved state. Hew much radon which is dissolved in the ground water, depends on the amount or radioactive elements in and surrounding the ground- water bearing strata and the ground water flow rate. The radon level of ground water is usually less than 1000 pCi/1, but may in singular cases be much higher; levels above 1 ⁇ Ci/1 has been found. If ground water containing dissolved radon is used as a water source, the water would when drawn at the surface liberate radon to the surrounding atmosphere and this is today commonly regarded as representing a non-negligible health risk in areas with radon-containing ground water.
• Another method is to place a alpha-particle track detector in a water container, e.g. in a toilet cistern for a certain period and then remove the detector and forward it to a laboratory for analysis.
• the latter method has, however, turned out to be completely unsuitable for a quantitative determination of the radon content of ground water.
• a first object in this connection is to avoid contact between the liquid and a surrounding atmosphere.
• a second object is to avoid a contaminitation of the device used with the method according to the invention and a further object is that the device with the sample contained shall be used directly in the final analysis, ' without any retapping into special sample containers being necessary.
• Figure 1 is a perspective view of the flexible inner container during filling.
• Figure 2 is a perspective view of the placement of the flexible container in the rigid container
• Figure 3 is a schematic view through the sealed container.
• the device of the Figure comprises a first container 1 which for instance may be a commercially available colostomi bag or a urine bag equipped with a plastic tube 2 for filling the bag.
• the bag 1 is watertight and preferably fluidtight and is provided with a one-way valve 3 which prevents outflow as well as possibility for closing the filling device, e.g. the plastic tube 2 by means of- a cap and/or a clip 4.
• the one-way valve 3 may most simply be a flap which prevents outflow, provided in connection with the filling device or the tube 2.
• the bag 1 Before filling takes place, the bag 1 is completely evacuated and the filling takes place by the filling device or tube 2 being inserted for instance in a water tap 5, as the tap is opened, such that the tube 2 catches the water before the water flow has issued from the tap opening.
• the bag 1 may during the filling be placed in the hand or on a tray.
• the bag 1 is made of a transparent plastic material such as polyethene and provided with printed strokes which indicates an approximate filling volume.
• the filling device 2 is drawn away from the tap and closed with the cap or a clip 4 which are placed on the tube, whereafter the bag is being wiped on the outside and placed in another container 6 of definite shape and whose size is adapted to the bag 1.
• the second container 6 After the bag 1 has been placed in the second container 6, this will be closed by means of a suitable gastight closure device.
• a suitable gastight closure device In connection with for instance gamma-spectrometric analysis of radon in water it is necessary that the second container 6 has a defined shape and geometry and that the detector used for the analysis has been calibrated for this geometry.
• the second container is thus a specially made can 6 of impact resistant polystyrene.
• a closure or film 7 of aluminium is placed over the bag 1 in the plastic can 6 and secured by welding with for instance an electric iron. Then the plastic can 6 is closed with a further lid 8. The sample is hence immediately after tapping sealed in the final analysis packaging.
• the analysis packaging i.e. the bag 1 and the second or outer sample container 6, it can now be performed an immediate determination of the radioactivity of the sample, measured in becquerel.
• a scintillisation detector in the form of a sodium iodide crystal.
• the scintillisation detector detects the gamma radiation emitted by the decay of radon daughters.
• the measured activity will give a correct determination of the radon content of the ground water.
• a determination of other isotopes and substances and. compounds in the liquid may also be made by using the device, i.e. the analysis packaging according to the present invention. If appropriate, alpha-particle-detectors might of course also be employed when using the analysis packaging according to the present invention.
• the device according to the invention may be made of other materials and that other filling devices and closure devices may be used than those mentioned herein, if only the .material and closure devices are -fluid- or gastight.
• the bag may have a shape which for instance is closely adapted to the rigid container, but may also be foldable and so flexible that it by insertion in the rigid container will adapt its shape to a satisfying degree, such that one may see this as a reproducible filling of the container volume.

Landscapes

• Health & Medical Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Biochemistry (AREA)
• Physics & Mathematics (AREA)
• Hydrology & Water Resources (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Hematology (AREA)
• Clinical Laboratory Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Sampling And Sample Adjustment (AREA)
• Measurement Of Radiation (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19891624

Family Applications (1)

Country Status (7)

Families Citing this family (7)

Family Cites Families (4)

• 1989
  • 1989-01-13 NO NO890163A patent/NO168670C/no unknown
• 1990
  • 1990-01-12 EP EP90901696A patent/EP0453469A1/de not_active Withdrawn
  • 1990-01-12 AU AU48396/90A patent/AU4839690A/en not_active Abandoned
  • 1990-01-12 JP JP2502197A patent/JPH04501173A/ja active Pending
  • 1990-01-12 FI FI913371A patent/FI913371A7/fi not_active Application Discontinuation
  • 1990-01-12 WO PCT/NO1990/000009 patent/WO1990008308A1/en not_active Ceased
  • 1990-01-12 BR BR909007024A patent/BR9007024A/pt not_active Application Discontinuation

Non-Patent Citations (1)

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