FI59172B - FOERFARANDE FOER KVANTITATIV BESTAEMNING AV I VAETSKOR LOESTA GASER OCH VID FOER FOERFARANDET ANVAENDBAR GASSEPARERINGSANORDNING - Google Patents

Description

ΓβΙ «« ANNOUNCEMENT 59172 ΛΓα lBJ (11) UTLÄGGNINGSSKRIFT 0 '' C (4S) Paierlt ^ i5elatUy ^ (51) Kv.lk?/IntXI.3 g 01 N 33/18 FINLAND —FINLAND (21) Pwnttlh »k« imw - PKUtnatalni 701755 (22) Hakamitpthr · - Antöknlnpdtj 01.06.TÖ (23) AlkupUvi — GIM | h «ttd« g 01.06.78 (41) Has become stuck - Blivlt offentllf 02.12.79

Patent] · Register Board .... .........

_ '(44) Date of publication of the notice. -

Patent · och registerstyrelsen Amaiun uti »jd och utUkrtftcn pubiicurtd 27-02.81 (32) (33) (31) Pyydetty ctuolkcu» —Begird prloritut (71) (72) Ari Heimo Kalevi Salonen, Evontie 23, 16900 Lammi,

The present invention relates to a method for the quantitative determination of gases dissolved in liquids and to a gas separation apparatus used in the method. for the quantitative determination of dissolved gases by dispensing a liquid sample containing the gas components to be analyzed into a bubbling chamber in which the gases dissolved in the sample are washed away with a carrier gas, optionally continuously adding a gas-releasing reagent.

The method according to the invention is characterized in that the carrier gas bubbling through the sinter plate transports the excess liquid with it to the liquid separator, where the gas bubbles disintegrate and the liquid flows down the pipe walls into the waste collector with an analyzer, a thermal gas analyzer, a gas chromatograph, a mass spectrometer, an absorption or fluorescence spectrometer or a conductometer, or a combination of the above-mentioned analytical instruments.

The invention also relates to a gas separation device for use in the method according to the invention, by means of which gases dissolved in a liquid are introduced into the gas phase, 59172 from which they can be quantified. The device according to the invention is characterized in that it comprises a bubbling chamber 1 provided with a sample feeding member 5 and. reagent solution and carrier gas supply lines U and 3, a sinter plate 6 and optionally a heating jacket, and a liquid separator 2 connected to the bubbling chamber, provided with a tank for the liquid separated from the sample and possibly a cooling jacket.

The sample supply member 5 on the side of the bubbling chamber 1 is preferably a tube with a water trap.

According to a preferred embodiment, the sample solution is injected into the bubbling chamber 1 so as to provide a horizontal vortex flow inside the chamber.

In this case, the sample is in the chamber for a short time as an almost annular strip, which has the advantage that the volume corresponding to the injected liquid leaving the chamber 1 is closest to the liquid already in the chamber. waste away.

The gas separation device according to the invention is very versatile. It can determine several different gases, and the number of samples can vary within wide limits (about 500x). The method is also suitable for continuous monitoring of gas concentration. The sensitivity to be achieved is very high because the method has no blank value at all. The reproducibility is as good as in the best known methods, and in addition the speed of the new method is decisively higher due to the fact that the use of the method requires nothing more than the injection of untreated samples into the device.

Systems are known for analyzing carbon dioxide or other gases and stabilizing the gas content of the liquid. The essential differences between the new method and the previous methods are: - continuous supply of acid - continuous removal of excess liquid - removal of liquid in the same way as gas - capillary force water trap in the injection tube.

The sample previously washed with carrier gas had to be removed manually and it was not possible to continuously feed the chamber with, for example, acid to convert carbonates to free carbon dioxide, as the amount of liquid in the chamber must be exactly constant for good reproducibility 3,5172 (unless an integrator is used). The manual dosing of chemicals and the subsequent wait to ensure the removal of impurity gases and the removal of waste liquid cause about a fourfold increase in the analysis time compared to the new method. Apart from the ease and accuracy of the results due to the acceleration of the work, the new method keeps the bubble chamber liquid volume exactly constant and, for total carbon dioxide, a more uniform baseline gas concentration compared to the previous method. In the known method, the basal level does not remain stable due to larger variations in the concentration of the acid and the need to use a more concentrated acid.

The device according to the invention and its operation will be explained below with reference to Figures „1 and 2.

Figure 1 shows a preferred device arrangement in which the sample supply means is an injection plug, and Figure 2 shows a bubbling chamber in which the sample supply means is a tube with a water trap. It should be mentioned that the water trap is based on capillary force.

For example, the operation of the device is as follows: a) inserting the injection needle through the injection plug h) injecting the sample into the bubbling chamber (preferably tangentially) c) removing the injection needle to take a new sample.

The size of the bubbling chamber (1) is not critical. A good chamber suitable for general use is obtained from a sinter with a diameter of 30 mm, whereby the volume of the bubbling part can be about 10-15 ml. Larger chambers can be used to analyze larger volumes of liquid, but smaller chambers can be used for faster analysis and slightly better reproducibility.

The gases separated from the liquid in the bubbling chamber can be determined in a known manner, for example by means of an infrared gas analyzer, a thermal gas analyzer, gas chromatography, a mass spectrometer, an absorption or fluorescence spectrometer, conductometrically, or a combination of the above.

The device according to the invention has a wide range of applications. It makes it possible to determine the concentration of gases dissolved in liquids or chemically gaseous substances more quickly and accurately than before. These include, for example, carbon dioxide, carbon monoxide, CH 2, nitrogen, oxygen, hydrogen, and many other organic gases. The bubbling chamber can also be provided with a heating jacket, so that the separation of certain gases can be enhanced.

The method is suitable for the determination of both very small concentrations (with carbon dioxide approximately 1 μM _1 Γ liter) and virtually any concentration, provided that the gases remain in the sample for the time required for injection, as the sample volume can be varied at least 5 μl to 2 ml and linear. e.g., for carbon dioxide, using an infrared gas analyzer, 0-20 mM liters Using suitable columns, e.g., gas chromatograph 11a can run multiple gases from the same sample simultaneously. The sample does not require any pre-treatment.

The gas separator according to the invention can be used, for example, to determine the total carbon dioxide content of the sample or the free carbon dioxide content. The device can then be used to perform 1-3 analyzes per minute, depending on the flow rate used. The variance of the results is only about 0.5% of the mean in the range of 1-20 mg (CO 2) C per liter 1.

In the following examples, the analysis apparatus shown in Figure 1 has been used. An infrared analyzer (liras 2T, manufactured by Hartman & Braun) was used as the carbon dioxide analyzer. The chemically bound carbon dioxide was converted to free carbon dioxide by introducing 1 ml of oxalic acid solution into the bubbling chamber. Assays were performed at room temperature.

Example 1

Inorganic carbon dissolved in water (total CO 2 -C assay) The sample was lake water containing 2.8 mg of carbon per liter. A sample was taken into a glass dosing syringe (2 ml) to obtain a bubble-free sample. The tip of the syringe was inserted through a silicone stopper and the sample was injected into the bubbling chamber to provide horizontal vortex flow inside the chamber. The injection needle was removed immediately thereafter. The flow rate of oxygen used as the carrier gas was 300 ml min. In the bubbling chamber, the carbonates react with the acid to form free carbon dioxide, which the carrier gas then carried to the analyzer. The remaining excess water escaped with the gas bubbles into the water separator. Carbon dioxide was analyzed using a 150 mm measuring cuvette and the result was recorded on a recorder. Calibration was similarly performed using a standard solution of sodium hydrogen carbonate in carbon dioxide-free water. The peak heights obtained were directly proportional to the amount of total carbon dioxide. The analysis took time Uo s and the standard deviation was 0.17%.

Example 2

Determination of gaseous organic carbon dissolved in water The sample was deoxygenated lake water containing 3.3 mg of gaseous carbon, per liter (mainly methane). The assay conditions were the same as in the previous example, except that the gas from the water separator was first passed through a dry carbon dioxide absorption charge and then through a 950 ° C catalyst zone to the analyzer. Inorganic carbon was quantitatively removed from the absorption charge and upon combustion, all organic gases burned to carbon dioxide, which was analyzed with an infrared gas analyzer. In this case, the calibration could be performed as in Example 1, but using the peak areas. The analysis took 1 min with a standard deviation of 1.3% of the mean.

Claims (3)

5,591 72 A method for the quantitative determination of gases dissolved in liquids by feeding a liquid sample containing the gas components to be analyzed into a bubbling chamber (1), in which the gases dissolved in the sample are washed away with a carrier gas, optionally continuously ), in which the gas bubbles disintegrate and the liquid flows down the pipe walls into the waste pipe, while the gas continues to the analyzer, after which the gases to be analyzed are determined in a manner known per se, for example infrared analyzer, , or a combination of the above analytical equipment. A method according to claim 1, characterized in that the sample solution is injected into the bubbling chamber (1) so as to provide a horizontal vortex flow inside the chamber. Gas separation device for use in the method according to claim 1, characterized in that it comprises a bubbling chamber (1) provided with a sample supply member (5) and reagent solution and carrier gas supply lines (k and 3) »sinter plate (6) and optionally a heating jacket , and a liquid separator (2) connected to the bubbling chamber, provided with a tank for the liquid separated from the sample, and possibly a cooling jacket. Device according to Claim 3, characterized in that the sample supply element (5) on the side of the bubbling chamber (1) is a tube with a water trap.